Treasure Roundup

Ages 6–8 · 12 minutes · Math

Find hidden treasure, explore Banana Bay and estimate the seashells on Shelly Shores!

In this rounding and estimation lesson, students will learn and practice:

- Making thoughtful estimates about groups of objects
- Estimating quantities of unknown items in the tens and hundreds
- Efficiency of using estimates for large groups of items
- Rounding to the nearest ten and hundred with rounding tables
- Estimating sums by rounding to the nearest hundred

Part of

Estimation and Rounding

Standards alignment

Common Core State Standards

3.NBT.A.1 — Use place value understanding to round whole numbers to the nearest 10 or 100.
2.NBT.B.7 — Add and subtract within 1000, using concrete models or drawings and strategies based on place value, properties of operations, and/or the relationship between addition and subtraction; relate the strategy to a written method. Understand that in adding or subtracting three-digit numbers, one adds or subtracts hundreds and hundreds, tens and tens, ones and ones; and sometimes it is necessary to compose or decompose tens or hundreds.
2.NBT.B.6 — Add up to four two-digit numbers using strategies based on place value and properties of operations.

Alabama

MA19.3.10 — Identify the nearest 10 or 100 when rounding whole numbers, using place value understanding.
MA19.2.11 — Use a variety of strategies to add up to four two-digit numbers.
MA19.3.8 — Determine and justify solutions for two-step word problems using the four operations and write an equation with a letter standing for the unknown quantity. Determine reasonableness of answers using number sense, context, mental computation, and estimation strategies including rounding.
MA19.2.12 — Add and subtract within 1000 using concrete models or drawings and strategies based on place value, properties of operations, and/or the relationship between addition and subtraction; relate the strategy to a written method.

Alaska

3.NBT.1 — Use place value understanding to round whole numbers to the nearest 10 or 100.
2.NBT.6 — Add up to four two-digit numbers using strategies based on place value and properties of operations.
2.NBT.7 — Add and subtract using numbers up to 1000. Use: • concrete models or drawings and strategies based on place value • properties of operations • and/or relationship between addition and subtraction. Relate the strategy to a written method and explain the reasoning used. Demonstrate in adding or subtracting three-digit numbers, hundreds and hundreds are added or subtracted, tens and tens are added or subtracted, ones and ones are added or subtracted and sometimes it is necessary to compose a ten from ten ones or a hundred from ten tens.
3.OA.8 — Solve and create two-step word problems using any of the four operations. Represent these problems using equations with a symbol (box, circle, question mark) standing for the unknown quantity. Assess the reasonableness of answers using mental computation and estimation strategies including rounding.
1.CC.6 — Estimate how many and how much in a given set to 20 and then verify estimate by counting.

Arizona

3.NBT.A.1 — Use place value understanding to round whole numbers to the nearest 10 or 100.
2.NBT.B.7 — Demonstrate understanding of addition and subtraction within 1000, connecting objects or drawings to strategies based on place value (including multiples of 10), properties of operations, and/or the relationship between addition and subtraction. Relate the strategy to a written form. See Table 1.
3.OA.D.10 — When solving problems, assess the reasonableness of answers using mental computation and estimation strategies including rounding.
2.NBT.B.6 — Add up to three two-digit numbers using strategies based on place value and properties of operations.

Arkansas

3.NPV.1 — Round four-digit whole numbers to the nearest 10 or 100, using place value understanding.
2.CAR.3 — Add up to four two-digit numbers with sums not exceeding 100 using strategies based on place value and properties of operations.
2.CAR.6 — Use concrete models, drawings, or equations to solve addition and subtraction problems within 1000.

California

2.NBT.7.1 — Use estimation strategies to make reasonable estimates in problem solving.
3.NBT.A.1 — Use place value understanding to round whole numbers to the nearest 10 or 100.
2.NBT.B.7 — Add and subtract within 1000, using concrete models or drawings and strategies based on place value, properties of operations, and/or the relationship between addition and subtraction; relate the strategy to a written method. Understand that in adding or subtracting three-digit numbers, one adds or subtracts hundreds and hundreds, tens and tens, ones and ones; and sometimes it is necessary to compose or decompose tens or hundreds.
3.OA.D.8 — Solve two-step word problems using the four operations. Represent these problems using equations with a letter standing for the unknown quantity. Assess the reasonableness of answers using mental computation and estimation strategies including rounding.

Colorado

3.NBT.A.1 — Use place value understanding to round whole numbers to the nearest 10 or 100.
2.NBT.B.7 — Add and subtract within 1000, using concrete models or drawings and strategies based on place value, properties of operations, and/or the relationship between addition and subtraction; relate the strategy to a written method. Understand that in adding or subtracting three-digit numbers, one adds or subtracts hundreds and hundreds, tens and tens, ones and ones; and sometimes it is necessary to compose or decompose tens or hundreds.
3.OA.D.8 — Solve two-step word problems using the four operations. Represent these problems using equations with a letter standing for the unknown quantity. Assess the reasonableness of answers using mental computation and estimation strategies including rounding. (This evidence outcome is limited to problems posed with whole numbers and having whole-number answers; students should know how to perform operations in the conventional order of operations when there are no parentheses to specify a particular order.)

Connecticut

3.NBT.A.1 — Use place value understanding to round whole numbers to the nearest 10 or 100.
2.NBT.B.6 — Add up to four two-digit numbers using strategies based on place value and properties of operations.
2.NBT.B.7 — Add and subtract within 1000, using concrete models or drawings and strategies based on place value, properties of operations, and/or the relationship between addition and subtraction; relate the strategy to a written method. Understand that in adding or subtracting three-digit numbers, one adds or subtracts hundreds and hundreds, tens and tens, ones and ones; and sometimes it is necessary to compose or decompose tens or hundreds.
4.NBT.A.3 — Use place value understanding to round multi-digit whole numbers to any place.

Delaware

3.NBT.A.1 — Use place value understanding to round whole numbers to the nearest 10 or 100.
3.NBT.A.2 — Fluently add and subtract within 1000 using strategies and algorithms based on place value, properties of operations, and/or the relationship between addition and subtraction.
3.OA.D.8 — Solve two-step word problems using the four operations. Represent these problems using equations with a letter standing for the unknown quantity. Assess the reasonableness of answers using mental computation and estimation strategies including rounding.

Florida

MA.3.NSO.1.4 — Round whole numbers from 0 to 1,000 to the nearest 10 or 100.
MA.K12.MTR.6.1 — Assess the reasonableness of solutions. Mathematicians who assess the reasonableness of solutions: • Estimate to discover possible solutions. • Use benchmark quantities to determine if a solution makes sense. • Check calculations when solving problems. • Verify possible solutions by explaining the methods used. • Evaluate results based on the given context.
MA.2.NSO.1.4 — Round whole numbers from 0 to 100 to the nearest 10.
MA.2.NSO.2.4 — Explore the addition of two whole numbers with sums up to 1,000. Explore the subtraction of a whole number from a whole number, each no larger than 1,000.

Georgia

3.NR.1.3 — Use place value understanding to round whole numbers within up to 1000 to the nearest 10 or 100.
3.NR.1 — Use place value reasoning to represent, read, write, and compare numerical values up to 10,000 and round whole numbers up to 1,000.
3.PAR.2.1 — Fluently add and subtract within 1000 to solve problems.

Hawaii

3.NBT.A.1 — Use place value understanding to round whole numbers to the nearest 10 or 100.
3.NBT.A.2 — Fluently add and subtract within 1000 using strategies and algorithms based on place value, properties of operations, and/or the relationship between addition and subtraction.
3.OA.D.8 — Solve two-step word problems using the four operations. Represent these problems using equations with a letter standing for the unknown quantity. Assess the reasonableness of answers using mental computation and estimation strategies including rounding.

Idaho

3.NBT.A.1 — Round a whole number to the tens or hundreds place, using place value understanding or a visual representation.
2.NBT.B.7.a — Understand that in adding or subtracting three-digit numbers, one adds or subtracts hundreds and hundreds, tens and tens, ones and ones.
3.OA.D.8.b — Assess the reasonableness of answers using mental computation and estimation strategies, including rounding.
2.NBT.B.7 — Add and subtract whole numbers within 1,000, by using physical, visual, and symbolic representations, with an emphasis on place value, properties of operations, and/or the relationships between addition and subtraction.

Illinois

3.NBT.A.1 — Use place value understanding to round whole numbers to the nearest 10 or 100.
2.NBT.B.7 — Add and subtract within 1000, using concrete models or drawings and strategies based on place value, properties of operations, and/or the relationship between addition and subtraction; relate the strategy to a written method. Understand that in adding or subtracting three-digit numbers, one adds or subtracts hundreds and hundreds, tens and tens, ones and ones; and sometimes it is necessary to compose or decompose tens or hundreds.
2.NBT.B.6 — Add up to four two-digit numbers using strategies based on place value and properties of operations.
3.OA.D.8 — Solve two-step word problems using the four operations. Represent these problems using equations with a letter standing for the unknown quantity. Assess the reasonableness of answers using mental computation and estimation strategies including rounding.

Indiana

3.NS.6 — Use place value understanding to round two- and three-digit whole numbers to the nearest 10 or 100.
2.CA.2 — Using number sense and place value strategies, add and subtract within 1,000, including composing and decomposing tens and hundreds. Use models, drawings, and strategies based on place value, properties of operations, and/or the relationship between addition and subtraction; describe the strategy and explain the reasoning used.
PS.8 — Look for and express regularity in repeated reasoning.

Iowa

3.NBT.A.1 — Round whole numbers to the nearest 10 or 100 within the range of 0–1,000. For example, rounding 643 to the nearest 10 would be 640; to the nearest 100 would be 600.
2.NBT.B.6 — Add up to four two-digit numbers using strategies based on place value and properties of operations.
2.NBT.B.7 — Add and subtract within 1,000, using concrete models or drawings and strategies based on place value, properties of operations, and/or the relationship between addition and subtraction; relate the strategy to a written method. Understand that in adding or subtracting three-digit numbers, one adds or subtracts hundreds and hundreds, tens and tens, ones and ones; and sometimes it is necessary to compose or decompose tens or hundreds.
SMP7 — Look for and make use of structure.

Kansas

3.NBT.1 — Use place value understanding to round whole numbers to the nearest 10 or 100.
2.NBT.6 — Add up to four two-digit numbers using strategies based on place value and properties of operations.
3.NBT.2 — Fluently (efficiently, accurately, & flexibly) add and subtract within 1000 using strategies (e.g. composing/decomposing by like base-10 units, using friendly or benchmark numbers, using related equations, compensation, number line, etc.) and algorithms (including, but not limited to: traditional, partial-sums, etc.) based on place value, properties of operations, and/or the relationship between addition and subtraction.
3.OA.8 — Solve two-step word problems using any of the four operations. Represent these problems using both situation equations and/or solution equations with a letter or symbol standing for the unknown quantity. Assess the reasonableness of answers using mental computation and estimation strategies including rounding. This standard is limited to problems posed with whole numbers and having whole-number answers.

Kentucky

KY.3.NBT.1 — Use place value understanding to round whole numbers to the nearest 10 or 100.
KY.2.NBT.6 — Add up to four two-digit numbers using strategies based on place value and properties of operations.
KY.2.NBT.7 — Add and subtract within 1000.
KY.3.OA.8 — Use various strategies to solve two-step word problems using the four operations (involving only whole numbers with whole number answers). Represent these problems using equations with a letter standing for the unknown quantity. Assess the reasonableness of answers using mental computation and estimation strategies including rounding.

Louisiana

3.NBT.A.1 — Use place value understanding to round whole numbers to the nearest 10 or 100.
2.NBT.B.7 — Add and subtract within 1000 using concrete models or drawings and strategies based on place value, properties of operations, and/or the relationship between addition and subtraction; justify the reasoning used with a written explanation. Understand that in adding or subtracting three-digit numbers, one adds or subtracts hundreds and hundreds, tens and tens, ones and ones; and sometimes it is necessary to compose or decompose tens or hundreds.
3.OA.D.8 — Solve two-step word problems using the four operations. Represent these problems using equations with a letter standing for the unknown quantity. Assess the reasonableness of answers using mental computation and estimation strategies including rounding.

Maine

3.NBT.A.1 — Use place value understanding to round whole numbers to the nearest 10 or 100.
2.NBT.B.7 — Add and subtract within 1000, using concrete models or drawings and strategies based on place value, properties of operations, and/or the relationship between addition and subtraction; relate the strategy to a written method. Understand that in adding or subtracting three-digit numbers, one adds or subtracts hundreds and hundreds, tens and tens, ones and ones; and sometimes it is necessary to compose or decompose tens or hundreds.
3.NBT.A.2 — Fluently add and subtract within 1000 using strategies and algorithms based on place value, properties of operations, and/or the relationship between addition and subtraction.
3.OA.D.8 — Solve two-step word problems using the four operations. Represent these problems using equations with a letter standing for the unknown quantity. Assess the reasonableness of answers using mental computation and estimation strategies including rounding.

Maryland

3.NBT.A.1 — Use place value understanding to round whole numbers to the nearest 10 or 100.
2.NBT.B.7 — Add and subtract within 1000, using concrete models or drawings and strategies based on place value, properties of operations, and/or the relationship between addition and subtraction; relate the strategy to a written method. Understand that in adding or subtracting three-digit numbers, one adds or subtracts hundreds and hundreds, tens and tens, ones and ones; and sometimes it is necessary to compose or decompose tens or hundreds.
2.NBT.B.6 — Add up to four two-digit numbers using strategies based on place value and properties of operations.
3.OA.D.8 — Solve two-step word problems using the four operations. Represent these problems using equations with a letter standing for the unknown quantity. Assess the reasonableness of answers using mental computation and estimation strategies including rounding.

Massachusetts

3.NBT.A.1 — Use place value understanding to round whole numbers to the nearest 10 or 100.
2.NBT.B.6 — Add up to four two-digit numbers using strategies based on place value and properties of operations.
3.NBT.A.2 — Fluently add and subtract within 1,000 using strategies and algorithms based on place value, properties of operations, and/or the relationship between addition and subtraction.
3.OA.D.8 — Solve two-step word problems using the four operations for problems posed with whole numbers and having whole number answers. Represent these problems using equations with a letter standing for the unknown quantity. Assess the reasonableness of answers using mental computation and estimation strategies, including rounding.

Michigan

3.NBT.A.1 — Use place value understanding to round whole numbers to the nearest 10 or 100.
2.NBT.B.7 — Add and subtract within 1000, using concrete models or drawings and strategies based on place value, properties of operations, and/or the relationship between addition and subtraction; relate the strategy to a written method. Understand that in adding or subtracting three-digit numbers, one adds or subtracts hundreds and hundreds, tens and tens, ones and ones; and sometimes it is necessary to compose or decompose tens or hundreds.
3.OA.D.8 — Solve two-step word problems using the four operations. Represent these problems using equations with a letter standing for the unknown quantity. Assess the reasonableness of answers using mental computation and estimation strategies including rounding.
2.NBT.B.6 — Add up to four two-digit numbers using strategies based on place value and properties of operations.

Minnesota

2.1.1.4 — Round numbers up to the nearest 10 and 100 and round numbers down to the nearest 10 and 100. For example: If there are 17 students in the class and granola bars come 10 to a box, you need to buy 20 bars (2 boxes) in order to have enough bars for everyone.
2.1.2.3 — Estimate sums and differences up to 100. For example: Know that 23 + 48 is about 70.
3.1.1.4 — Round numbers to the nearest 10,000, 1000, 100 and 10. Round up and round down to estimate sums and differences. For example: 8726 rounded to the nearest 1000 is 9000, rounded to the nearest 100 is 8700, and rounded to the nearest 10 is 8730. Another example: 473 – 291 is between 400 – 300 and 500 – 200, or between 100 and 300.
2.1.2.4 — Use mental strategies and algorithms based on knowledge of place value and equality to add and subtract two-digit numbers. Strategies may include decomposition, expanded notation, and partial sums and differences. For example: Using decomposition, 78 + 42, can be thought of as: 78 + 2 + 20 + 20 = 80 + 20 + 20 = 100 + 20 = 120 and using expanded notation, 34 - 21 can be thought of as: 30 + 4 – 20 – 1 = 30 – 20 + 4 – 1 = 10 + 3 = 13.

Mississippi

3.NBT.1 — Use place value understanding to round whole numbers to the nearest 10 or 100.
2.NBT.6 — Add up to four two-digit numbers using strategies based on place value and properties of operations.
2.NBT.7 — Add and subtract within 1000, using concrete models or drawings and strategies based on place value, properties of operations, and/or the relationship between addition and subtraction; relate the strategy to a written method. Understand that in adding or subtracting three-digit numbers, one adds or subtracts hundreds and hundreds, tens and tens, ones and ones; and sometimes it is necessary to compose or decompose tens or hundreds.

Missouri

3.NBT.A.1 — Round whole numbers to the nearest 10 or 100.
3.RA.D.10 — Interpret the reasonableness of answers using mental computation and estimation strategies including rounding.
2.NBT.B.8 — Add or subtract within 1000, and justify the solution.

Montana

3.NBT.A.1 — Use place value understanding to round whole numbers to the nearest 10 or 100.
2.NBT.B.6 — Add up to four two-digit numbers using strategies based on place value and properties of operations.
2.NBT.B.7 — Add and subtract within 1000, using concrete models or drawings and strategies based on place value, properties of operations, and/or the relationship between addition and subtraction; relate the strategy to a written method. Understand that in adding or subtracting three-digit numbers, one adds or subtracts hundreds and hundreds, tens and tens, ones and ones; and sometimes it is necessary to compose or decompose tens or hundreds.

Nebraska

3.A.1.b — Determine the reasonableness of whole number sums and differences using estimations and number sense.
2.N.4.d — Add up to three two-digit numbers using strategies based on place value and understanding of properties.
2.N.4.e — Add and subtract within 1,000 using concrete models, drawings, and strategies that reflect an understanding of place value and the properties of operations.

Nevada

3.NBT.A.1 — Use place value understanding to round whole numbers to the nearest 10 or 100.
3.NBT.A.2 — Fluently add and subtract within 1000 using strategies and algorithms based on place value, properties of operations, and/or the relationship between addition and subtraction.
3.OA.D.8 — Solve two-step word problems using the four operations. Represent these problems using equations with a letter standing for the unknown quantity. Assess the reasonableness of answers using mental computation and estimation strategies including rounding.

New Hampshire

3.NBT.A.1 — Use place value understanding to round whole numbers to the nearest 10 or 100.
3.NBT.A.2 — Fluently add and subtract within 1000 using strategies and algorithms based on place value, properties of operations, and/or the relationship between addition and subtraction.
2.NBT.B.7 — Add and subtract within 1000, using concrete models or drawings and strategies based on place value, properties of operations, and/or the relationship between addition and subtraction; relate the strategy to a written method. Understand that in adding or subtracting three-digit numbers, one adds or subtracts hundreds and hundreds, tens and tens, ones and ones; and sometimes it is necessary to compose or decompose tens or hundreds.

New Jersey

3.NBT.A.1 — Use place value understanding to round whole numbers to the nearest 10 or 100.
2.NBT.B.6 — Add up to four two-digit numbers using strategies based on place value and properties of operations.
2.NBT.B.7 — Add and subtract within 1000, using concrete models or drawings and strategies based on place value, properties of operations, and/or the relationship between addition and subtraction; relate the strategy to a written method. Understand that in adding or subtracting three-digit numbers, one adds or subtracts hundreds and hundreds, tens and tens, ones and ones; and sometimes it is necessary to compose or decompose tens or hundreds.

New Mexico

3.NBT.A.1 — Use place value understanding to round whole numbers to the nearest 10 or 100.
2.NBT.B.7 — Add and subtract within 1000, using concrete models or drawings and strategies based on place value, properties of operations, and/or the relationship between addition and subtraction; relate the strategy to a written method. Understand that in adding or subtracting three-digit numbers, one adds or subtracts hundreds and hundreds, tens and tens, ones and ones; and sometimes it is necessary to compose or decompose tens or hundreds.
3.OA.D.8 — Solve two-step word problems using the four operations. Represent these problems using equations with a letter standing for the unknown quantity. Assess the reasonableness of answers using mental computation and estimation strategies including rounding.

New York

NY-3.NBT.1 — Use place value understanding to round whole numbers to the nearest 10 or 100.
NY-2.NBT.7.b — Understand that in adding or subtracting up to three-digit numbers, one adds or subtracts hundreds and hundreds, tens and tens, ones and ones, and sometimes it is necessary to compose or decompose tens or hundreds.
NY-3.OA.8.b — Assess the reasonableness of answers using mental computation and estimation strategies including rounding.

North Carolina

NC.2.NBT.6 — Add up to three two-digit numbers using strategies based on place value and properties of operations.
NC.2.NBT.7 — Add and subtract, within 1,000, relating the strategy to a written method, using: • Concrete models or drawings • Strategies based on place value • Properties of operations • Relationship between addition and subtraction
NC.3.NBT.2 — Add and subtract whole numbers up to and including 1,000. • Use estimation strategies to assess reasonableness of answers. • Model and explain how the relationship between addition and subtraction can be applied to solve addition and subtraction problems. • Use expanded form to decompose numbers and then find sums and differences.

North Dakota

3.NO.NBT.2 — Apply place value understanding to round whole numbers to the nearest 10 or 100.
3.NO.NBT.3 — Add and subtract within 1000 using place value strategies, algorithms, and/or the relationship between addition and subtraction.
2.NO.NBT.3 — Add within 100 using place value strategies and/or the relationship between addition and subtraction.

Ohio

3.NBT.1 — Use place value understanding to round whole numbers to the nearest 10 or 100.
2.NBT.6 — Add up to four two-digit numbers using strategies based on place value and properties of operations.
2.NBT.7 — Add and subtract within 1,000, using concrete models or drawings and strategies based on place value, properties of operations, and/or the relationship between addition and subtraction; record the strategy with a written numerical method (drawings and, when appropriate, equations) and explain the reasoning used. Understand that in adding or subtracting three-digit numbers, hundreds are added or subtracted from hundreds, tens are added or subtracted from tens, ones are added or subtracted from ones; and sometimes it is necessary to compose or decompose tens or hundreds.
3.OA.8 — Solve two-step word problems using the four operations. Represent these problems using equations with a letter or a symbol, which stands for the unknown quantity. Assess the reasonableness of answers using mental computation and estimation strategies including rounding. This standard is limited to problems posed with whole numbers and having whole number answers. Students may use parentheses for clarification since algebraic order of operations is not expected.

Oklahoma

2.N.1.6 — Use place value understanding to round numbers to the nearest ten and nearest hundred (up to 1,000). Recognize when to round in real-world situations.
2.N.2.3 — Estimate sums and differences up to 100.
3.N.2.4 — Recognize when to round numbers and apply understanding to estimate sums and differences to the nearest ten thousand, thousand, hundred, and ten.

Oregon

3.NBT.A.1 — Use place value understanding to round whole numbers within 1000 to the nearest 10 or 100.
2.NBT.B.7 — Add and subtract within 1000 using concrete or visual representations and strategies based on place value, properties of operations, and/or the relationship between addition and subtraction. Relate the strategy to a written method and explain why sometimes it is necessary to compose or decompose tens or hundreds.
2.NBT.B.6 — Add up to four two-digit numbers using strategies based on place value and properties of operations and describe how two different strategies result in the same sum.

Pennsylvania

CC.2.1.3.B.1 — Apply place-value understanding and properties of operations to perform multi-digit arithmetic.

Rhode Island

3.NBT.A.1 — Use place value understanding to round whole numbers to the nearest 10 or 100.
2.NBT.B.6 — Add up to four two-digit numbers using strategies based on place value and properties of operations.
2.NBT.B.7 — Add and subtract within 1000, using concrete models or drawings and strategies based on place value, properties of operations, and/or the relationship between addition and subtraction; relate the strategy to a written method. Understand that in adding or subtracting three-digit numbers, one adds or subtracts hundreds and hundreds, tens and tens, ones and ones; and sometimes it is necessary to compose or decompose tens or hundreds.
3.OA.D.8 — Solve two-step word problems using the four operations for problems posed with whole numbers and having whole number answers. Represent these problems using equations with a letter standing for the unknown quantity. Assess the reasonableness of answers using mental computation and estimation strategies, including rounding.

South Carolina

3.NSBT.1 — Use place value understanding to round whole numbers to the nearest 10 or 100.
2.NSBT.6 — Add up to four two-digit numbers using strategies based on knowledge of place value and properties of operations.
2.PS.4c — Make assumptions and estimates to simplify complicated situations.
3.NSBT.2 — Add and subtract whole numbers fluently to 1,000 using knowledge of place value and properties of operations.

South Dakota

3.NBT.A.1 — Use place value understanding to round whole numbers to the nearest 10 or 100.
2.NBT.B.7 — Add and subtract within 1000, using concrete models or drawings and strategies based on place value, properties of operations, and/or the relationship between addition and subtraction; relate the strategy to a written method. Understand that in adding or subtracting three-digit numbers, one adds or subtracts hundreds and hundreds, tens and tens, ones and ones; and sometimes it is necessary to compose or decompose tens or hundreds.
3.OA.D.8 — Solve two-step word problems using the four operations. Represent these problems using equations with a letter standing for the unknown quantity. Assess the reasonableness of answers using mental computation and estimation strategies including rounding.

Tennessee

3.NBT.A.1 — Round whole numbers to the nearest 10 or 100 using understanding of place value and use a number line to explain how the number was rounded.
2.NBT.B.6 — Add up to four two-digit numbers using properties of operations and strategies based on place value.
3.NBT.A.2 — Fluently add and subtract within 1000 using strategies and algorithms based on place value, properties of operations, and/or the relationship between addition and subtraction.

Texas

3.2C — represent a number on a number line as being between two consecutive multiples of 10; 100; 1,000; or 10,000 and use words to describe relative size of numbers in order to round whole numbers; and
3.4B — round to the nearest 10 or 100 or use compatible numbers to estimate solutions to addition and subtraction problems;
3.1C — select tools, including real objects, manipulatives, paper and pencil, and technology as appropriate, and techniques, including mental math, estimation, and number sense as appropriate, to solve problems;
2.4B — add up to four two-digit numbers and subtract two-digit numbers using mental strategies and algorithms based on knowledge of place value and properties of operations;

Utah

3.NBT.1 — Use place value understanding to round whole numbers to the nearest 10 or 100.
3.OA.8.c — Assess the reasonableness of answers using mental computation and estimation strategies, including rounding.
3.NBT.2 — Fluently add and subtract within 1,000 using strategies and algorithms based on place value, properties of operations, and/or the relationship between addition and subtraction.

Vermont

3.NBT.A.1 — Use place value understanding to round whole numbers to the nearest 10 or 100.
2.NBT.B.7 — Add and subtract within 1000, using concrete models or drawings and strategies based on place value, properties of operations, and/or the relationship between addition and subtraction; relate the strategy to a written method. Understand that in adding or subtracting three-digit numbers, one adds or subtracts hundreds and hundreds, tens and tens, ones and ones; and sometimes it is necessary to compose or decompose tens or hundreds.
2.NBT.B.6 — Add up to four two-digit numbers using strategies based on place value and properties of operations.
3.OA.D.8 — Solve two-step word problems using the four operations. Represent these problems using equations with a letter standing for the unknown quantity. Assess the reasonableness of answers using mental computation and estimation strategies including rounding.

Virginia

3.CE.1b — Apply strategies (e.g., rounding to the nearest 10 or 100, using compatible numbers, using other number relationships) to estimate a solution for single-step or multistep addition or subtraction problems, including those in context, where addends or minuends do not exceed 1,000.
2.CE.1a — Apply strategies (e.g., rounding to the nearest 10, compatible numbers, other number relationships) to estimate a solution for single-step addition or subtraction problems, including those in context, where addends and minuends do not exceed 100.
2.NS.1g — Choose a reasonable estimate up to 1,000 when given a contextual problem (e.g., What would be the best estimate for the number of students in our school – 5, 50, or 500?).
3.CE.1a — Determine and justify whether an estimate or an exact answer is appropriate when solving single-step and multistep contextual problems involving addition and subtraction, where addends and minuends do not exceed 1,000.

Washington

3.NBT.A.1 — Use place value understanding to round whole numbers to the nearest 10 or 100.
3.NBT.A.2 — Fluently add and subtract within 1000 using strategies and algorithms based on place value, properties of operations, and/or the relationship between addition and subtraction.
3.OA.D.8 — Solve two-step word problems using the four operations. Represent these problems using equations with a letter standing for the unknown quantity. Assess the reasonableness of answers using mental computation and estimation strategies including rounding.

Washington, D.C.

3.NBT.A.1 — Use place value understanding to round whole numbers to the nearest 10 or 100.

West Virginia

M.3.12 — Use place value understanding to round whole numbers to the nearest 10 or 100.
M.2.11 — Add up to four two-digit numbers using strategies based on place value and properties of operations.
M.2.12 — Add and subtract within 1000, using concrete models or drawings and strategies based on place value, properties of operations and/or the relationship between addition and subtraction; relate the strategy to a written method. Understand that in adding or subtracting three-digit numbers, one adds or subtracts hundreds and hundreds, tens and tens, ones and ones and sometimes it is necessary to compose or decompose tens or hundreds.

Wisconsin

M.3.NBT.A.1 — Use place value understanding to generate estimates for problems in real-world situations, with whole numbers within 1,000, using strategies such as mental math, benchmark numbers, compatible numbers, and rounding. Assess the reasonableness of their estimates (e.g., Is my estimate too low or too high? What degree of precision do I need for this situation?).

Wyoming

3.NBT.E.1 — Use place value understanding to round whole numbers to the nearest 10 or 100.
2.NBT.E.7.B — Understand that in adding or subtracting three-digit numbers, add or subtract hundreds and hundreds, tens and tens, ones and ones.
3.OA.D.8.B — Assess the reasonableness of answers using mental computation and estimation strategies including rounding.
2.NBT.E.5 — Add and subtract within 100 using strategies based on place value, properties of addition, and/or the relationship between addition and subtraction.