Number Sense: Up to 99

Ages 4–6 · 14 minutes · Math

Build number sense for the numbers from 61 to 99

In this lesson, students will learn about the numbers from 61 to 99. They will practice counting using math cubes, rubber duckies, and bumblebees. They will explore representations of numbers up to 99 using ten rods and math cubes, and they will gain confidence working with larger numbers.

Part of

Number Sense: 21–100

Standards alignment

Common Core State Standards

1.NBT.B.2 — Understand that the two digits of a two-digit number represent amounts of tens and ones. Understand the following as special cases:
1.NBT.B.2.c — Understand that the two digits of a two-digit number represent amounts of tens and ones. Understand the following as special cases: the numbers 10, 20, 30, 40, 50, 60, 70, 80, 90 refer to one, two, three, four, five, six, seven, eight, or nine tens (and 0 ones).
K.CC.A.1 — Count to 100 by ones and by tens.
1.NBT.A.1 — Count to 120, starting at any number less than 120. In this range, read and write numerals and represent a number of objects with a written numeral.
1.NBT.C.5 — Given a two-digit number, mentally find 10 more or 10 less than the number, without having to count; explain the reasoning used.

Alabama

MA19.1.11 — Explain that the two digits of a two-digit number represent amounts of tens and ones.
MA19.1.11a — Identify a bundle of ten ones as a "ten."
MA19.1.11c — Identify the numbers 10, 20, 30, 40, 50, 60, 70, 80, 90 as one, two, three, four, five, six, seven, eight, or nine tens (and 0 ones).
MA19.1.10d — Represent a number of objects from 0 to 120 with a written numeral.
MA19.1.14 — Given a two-digit number, mentally find 10 more or 10 less than the number without having to count, and explain the reasoning used.

Alaska

1.CC.4 — Count a large quantity of objects by grouping into 10s and counting by 10s and 1s to find the quantity.
1.NBT.2 — Model and identify place value positions of two digit numbers. Include:
1.NBT.2.c — The numbers 10, 20, 30, 40, 50, 60, 70, 80, 90, refer to one, two, three, four, five, six, seven, eight or nine tens (and 0 ones).
K.CC.1 — Count to 100 by ones and by tens.
1.NBT.5 — Given a two-digit number, mentally find 10 more or 10 less than the number, without having to count; explain the reasoning used.

Arizona

1.NBT.B.2 — Understand that the two digits of a two-digit number represent amounts of tens and ones. Understand the following as special cases:
1.NBT.B.2.c — The numbers 10, 20, 30, 40, 50, 60, 70, 80, 90 refer to one, two, three, four, five, six, seven, eight, or nine tens (and 0 ones).
1.NBT.B.2.a — 10 can be thought of as a bundle of ten ones — called a "ten."
1.NBT.C.5 — Given a two-digit number, mentally find 10 more or 10 less than the number, without having to count.
K.CC.A.1 — Count to 100 by ones and by tens.

Arkansas

1.NPV.3 — Explain the place value of ones and tens in two-digit numbers, using concrete models, diagrams, numbers, or words.
1.NPV.4 — Read, write, and represent whole numbers up to 120, using concrete models or drawings, word form, base ten numerals, and expanded form.
1.NPV.1 — Count forward and back within 120 by ones and tens from any given whole number.
1.NPV.6 — Use mental strategies to find 10 more or 10 less than a given two-digit number.

California

1.NBT.A.1 — Count to 120, starting at any number less than 120. In this range, read and write numerals and represent a number of objects with a written numeral.
1.NBT.B.2 — Understand that the two digits of a two-digit number represent amounts of tens and ones. Understand the following as special cases:
1.NBT.B.2.c — The numbers 10, 20, 30, 40, 50, 60, 70, 80, 90 refer to one, two, three, four, five, six, seven, eight, or nine tens (and 0 ones).
1.NBT.C.5 — Given a two-digit number, mentally find 10 more or 10 less than the number, without having to count; explain the reasoning used.
K.CC.A.1 — Count to 100 by ones and by tens.

Colorado

1.NBT.B.2 — Understand that the two digits of a two-digit number represent amounts of tens and ones. Understand the following as special cases:
1.NBT.B.2.c — The numbers 10, 20, 30, 40, 50, 60, 70, 80, 90 refer to one, two, three, four, five, six, seven, eight, or nine tens (and 0 ones).
1.NBT.A.1 — Count to 120, starting at any number less than 120. In this range, read and write numerals and represent a number of objects with a written numeral.
1.NBT.C.5 — Given a two-digit number, mentally find 10 more or 10 less than the number, without having to count; explain the reasoning used.
K.CC.A.1 — Count to 100 by ones and by tens.

Connecticut

1.NBT.B.2 — Understand that the two digits of a two-digit number represent amounts of tens and ones. Understand the following as special cases:
1.NBT.B.2.c — The numbers 10, 20, 30, 40, 50, 60, 70, 80, 90 refer to one, two, three, four, five, six, seven, eight, or nine tens (and 0 ones).
1.NBT.A.1 — Count to 120, starting at any number less than 120. In this range, read and write numerals and represent a number of objects with a written numeral.
1.NBT.C.5 — Given a two-digit number, mentally find 10 more or 10 less than the number, without having to count; explain the reasoning used.
K.CC.A.1 — Count to 100 by ones and by tens.

Delaware

1.NBT.A.1 — Count to 120, starting at any number less than 120. In this range, read and write numerals and represent a number of objects with a written numeral.
1.NBT.B.2 — Understand that the two digits of a two-digit number represent amounts of tens and ones. Understand the following as special cases:
1.NBT.B.2.c — The numbers 10, 20, 30, 40, 50, 60, 70, 80, 90 refer to one, two, three, four, five, six, seven, eight, or nine tens (and 0 ones).
1.NBT.C.5 — Given a two-digit number, mentally find 10 more or 10 less than the number, without having to count; explain the reasoning used.
K.CC.A.1 — Count to 100 by ones and by tens.

Florida

MA.1.NSO.1.3 — Compose and decompose two-digit numbers in multiple ways using tens and ones. Demonstrate each composition or decomposition with objects, drawings and expressions or equations.
MA.1.NSO.2.3 — Identify the number that is one more, one less, ten more and ten less than a given two-digit number.
MA.K.NSO.2.1 — Recite the number names to 100 by ones and by tens. Starting at a given number, count forward within 100 and backward within 20.
MA.1.NSO.1.2 — Read numbers from 0 to 100 written in standard form, expanded form and word form. Write numbers from 0 to 100 using standard form and expanded form.

Georgia

1.NR.1.1 — Count within 120, forward and backward, starting at any number. In this range, read and write numerals and represent a number of objects with a written numeral.
1.NR.1.2 — Explain that the two digits of a 2-digit number represent the amounts of tens and ones.
1.NR.5.2 — Given a two-digit number, mentally find 10 more or 10 less than the number, without having to count; explain the reasoning used.
K.NR.2.1 — Count forward to 100 by tens and ones and backward from 20 by ones.

Hawaii

1.NBT.B.2 — Understand that the two digits of a two-digit number represent amounts of tens and ones. Understand the following as special cases:
1.NBT.B.2c — The numbers 10, 20, 30, 40, 50, 60, 70, 80, 90 refer to one, two, three, four, five, six, seven, eight, or nine tens (and 0 ones).
1.NBT.A.1 — Count to 120, starting at any number less than 120. In this range, read and write numerals and represent a number of objects with a written numeral.
1.NBT.C.5 — Given a two-digit number, mentally find 10 more or 10 less than the number, without having to count; explain the reasoning used.
K.CC.A.1 — Count to 100 by ones and by tens.

Idaho

1.NBT.B.2 — Understand that the two digits of a two-digit number represent amounts of tens and ones.
1.NBT.B.2.c — The numbers 10, 20, 30, 40, 50, 60, 70, 80, 90 refer to one, two, three, four, five, six, seven, eight, or nine tens (and zero ones).
K.CC.A.1 — Count to 100 by ones and by tens.
1.NBT.A.1 — Starting at a given number, count forward and backwards within 120 by ones. Skip count by twos to 20, by fives to 100, and by tens to 120. In this range, read and write numerals and represent a number of objects with a written numeral.

Illinois

1.NBT.B.2 — Understand that the two digits of a two-digit number represent amounts of tens and ones. Understand the following as special cases:
1.NBT.B.2.c — The numbers 10, 20, 30, 40, 50, 60, 70, 80, 90 refer to one, two, three, four, five, six, seven, eight, or nine tens (and 0 ones).
K.CC.A.1 — Count to 100 by ones and by tens.
1.NBT.A.1 — Count to 120, starting at any number less than 120. In this range, read and write numerals and represent a number of objects with a written numeral.
1.NBT.C.5 — Given a two-digit number, mentally find 10 more or 10 less than the number, without having to count; explain the reasoning used.

Indiana

1.NS.2 — Model place value concepts of two-digit numbers, multiples of 10, and equivalent forms of whole numbers using objects and drawings. (E)
K.NS.1 — Count to at least 100 by ones and tens. Count by one from any given number. (E)
1.NS.1 — Count to at least 120 by ones, fives, and tens from any given number. In this range, read and write numerals and represent a number of objects with a written numeral. (E)

Iowa

1.NBT.B.2 — Understand that the two digits of a two-digit number represent amounts of tens and ones. Understand the following as special cases.
1.NBT.B.2.c — The numbers 10, 20, 30, 40, 50, 60, 70, 80, 90 refer to one, two, three, four, five, six, seven, eight, or nine tens (and 0 ones).
1.NBT.A.1 — Count forward and backward starting with any given number within the range of 0–120, In this range, read and write numerals and represent a number of objects with a written numeral.
1.NBT.B.2.a — 10 can be thought of as a bundle of ten ones — called a "ten."
1.NBT.C.5 — Given a two-digit number, mentally find 10 more or 10 less than the number, without having to count; explain the reasoning used.

Kansas

1.NBT.2 — Understand that the two digits of a two-digit number represent amounts of tens and ones. Understand the following as special cases:
1.NBT.2.c — The numbers 10, 20, 30, 40, 50, 60, 70, 80, 90 refer to one, two, three, four, five, six, seven, eight, or nine tens (and 0 ones).
1.NBT.1 — Count to 120 (recognizing growth and repeating patterns), starting at any number less than 120. In this range, read and write numerals and represent a number of objects with a written numeral.
1.NBT.5 — Given a two-digit number, mentally find 10 more or 10 less than the number, without having to count; explain the reasoning used.
K.CC.1 — Count to 100 by ones and by tens and identify as a growth pattern.

Kentucky

KY.1.NBT.2 — Understand the two-digits of a two-digit number represent amounts of tens and ones. Understand the following as special cases:
KY.1.NBT.2.c — The numbers 10, 20, 30, 40, 50, 60, 70, 80, 90 refer to one, two, three, four, five, six, seven, eight or nine tens (and 0 ones).
KY.1.NBT.1.b — In this range, read and write numerals and represent a number of objects with a written numeral.
KY.1.NBT.5 — Given a two-digit number, mentally find 10 more or 10 less than the number, without having to count; explain the reasoning used.
KY.K.CC.1.a — Count to 100 by ones and by tens.

Louisiana

1.NBT.B.2 — Understand that the two digits of a two-digit number represent amounts of tens and ones. Understand the following as special cases:
1.NBT.B.2.c — The numbers 10, 20, 30, 40, 50, 60, 70, 80, 90 refer to one, two, three, four, five, six, seven, eight, or nine tens (and 0 ones).
K.CC.A.1 — Count to 100 by ones and by tens.
1.NBT.A.1 — Count to 120, starting at any number less than 120. In this range, read and write numerals and represent a number of objects with a written numeral.
1.NBT.C.5 — Given a two-digit number, mentally find 10 more or 10 less than the number, without having to count; explain the reasoning used.

Maine

1.NBT.B.2 — Understand that the two digits of a two-digit number represent amounts of tens and ones. Understand the following as special cases:
1.NBT.B.2c — The numbers 10, 20, 30, 40, 50, 60, 70, 80, 90 refer to one, two, three, four, five, six, seven, eight, or nine tens (and 0 ones).
K.CC.A.1 — Count to 100 by ones and by tens
1.NBT.A.1 — Count to 120, starting at any number less than 120. In this range, read and write numerals and represent a number of objects with a written numeral.
1.NBT.B.2a — 10 can be thought of as a bundle of ten ones - called a “ten.”

Maryland

1.NBT.B.2 — Understand that the two digits of a two-digit number represent amounts of tens and ones. Understand the following as special cases:
1.NBT.B.2.c — The numbers 10, 20, 30, 40, 50, 60, 70, 80, 90 refer to one, two, three, four, five, six, seven, eight, or nine tens (and 0 ones).
K.CC.A.1 — Count to 100 by ones and by tens.
1.NBT.A.1 — Count to 120, starting at any number less than 120. In this range, read and write numerals and represent a number of objects with a written numeral.
1.NBT.C.5 — Given a two-digit number, mentally find 10 more or 10 less than the number, without having to count; explain the reasoning used.

Massachusetts

1.NBT.B.2 — Understand that the two digits of a two-digit number represent amounts of tens and ones. Understand the following as special cases:
1.NBT.B.2.c — The numbers 10, 20, 30, 40, 50, 60, 70, 80, 90 refer to one, two, three, four, five, six, seven, eight, or nine tens (and 0 ones).
K.CC.A.1 — Count to 100 by ones and by tens.
1.NBT.A.1 — Count to 120, starting at any number less than 120. In this range, read and write numerals and represent a number of objects with a written numeral.
1.NBT.C.5 — Given a two-digit number, mentally find 10 more or 10 less than the number, without having to count; explain the reasoning used. Identify arithmetic patterns of 10 more and 10 less than using strategies based on place value.

Michigan

1.NBT.B.2 — Understand that the two digits of a two-digit number represent amounts of tens and ones. Understand the following as special cases:
1.NBT.B.2.c — The numbers 10, 20, 30, 40, 50, 60, 70, 80, 90 refer to one, two, three, four, five, six, seven, eight, or nine tens (and 0 ones).
1.NBT.A.1 — Count to 120, starting at any number less than 120. In this range, read and write numerals and represent a number of objects with a written numeral.
1.NBT.C.5 — Given a two-digit number, mentally find 10 more or 10 less than the number, without having to count; explain the reasoning used.
K.CC.A.1 — Count to 100 by ones and by tens.

Minnesota

1.1.1.1 — Use place value to describe whole numbers between 10 and 100 in terms of tens and ones. For example: Recognize the numbers 21 to 29 as 2 tens and a particular number of ones.
1.1.1.2 — Read, write and represent whole numbers up to 120. Representations may include numerals, addition and subtraction, pictures, tally marks, number lines and manipulatives, such as bundles of sticks and base 10 blocks.
1.1.1.4 — Find a number that is 10 more or 10 less than a given number. For example: Using a hundred grid, find the number that is 10 more than 27.
1.1.2.3 — Recognize the relationship between counting and addition and subtraction. Skip count by 2s, 5s, and 10s.

Mississippi

1.NBT.2 — Understand that the two digits of a two-digit number represent amounts of tens and ones. Understand the following as special cases:
1.NBT.2.c — The numbers 10, 20, 30, 40, 50, 60, 70, 80, 90 refer to one, two, three, four, five, six, seven, eight, or nine tens (and 0 ones).
1.NBT.5 — Given a two-digit number, mentally find 10 more or 10 less than the number, without having to count; explain the reasoning used.
1.NBT.1 — Count to 120, starting at any number less than 120. In this range, read and write numerals and represent a number of objects with a written numeral.
K.CC.1 — Count to 100 by ones and by tens.

Missouri

1.NBT.A.1 — Understand that 10 can be thought of as a bundle of 10 ones – called a “ten”.
1.NBT.A.2 — Understand two-digit numbers are composed of ten(s) and one(s).
K.NS.A.1 — Count to 100 by ones and tens.
1.NBT.B.6 — Calculate 10 more or 10 less than a given number mentally without having to count.
1.NS.A.2 — Read and write numerals and represent a number of objects with a written numeral.

Montana

1.NBT.B.2 — Understand that the two digits of a two-digit number represent amounts of tens and ones. Understand the following as special cases:
1.NBT.B.2.c — The numbers 10, 20, 30, 40, 50, 60, 70, 80, 90 refer to one, two, three, four, five, six, seven, eight, or nine tens (and 0 ones).
1.NBT.A.1 — Count to 120, starting at any number less than 120. In this range, read and write numerals and represent a number of objects with a written numeral.
1.NBT.C.5 — Given a two-digit number, mentally find 10 more or 10 less than the number, without having to count; explain the reasoning used.
K.CC.A.1 — Count to 100 by ones and by tens.
1.NBT.B.2.a — 10 can be thought of as a bundle of ten ones — called a "ten."

Nebraska

1.N.3.a — Understand 10 as a bundle, collection, or (more abstractly) composition of ten ones and that the two digits of a two-digit number represent a composition of some tens and some ones.
1.N.2.a — Count verbally by ones and tens within 120 starting at any given number.
1.N.3 — Base Ten: Students will represent and compare two-digit numbers to gain foundations for place value.
1.N.4.d — Mentally find 10 more or 10 less than a two-digit number without having to count and explain the reasoning used.

Nevada

1.NBT.A.1 — Count to 120, starting at any number less than 120. In this range, read and write numerals and represent a number of objects with a written numeral.
1.NBT.B.2 — Understand that the two digits of a two-digit number represent amounts of tens and ones. Understand the following as special cases:
1.NBT.B.2.c — The numbers 10, 20, 30, 40, 50, 60, 70, 80, 90 refer to one, two, three, four, five, six, seven, eight, or nine tens (and 0 ones).
1.NBT.C.5 — Given a two-digit number, mentally find 10 more or 10 less than the number, without having to count; explain the reasoning used.
K.CC.A.1 — Count to 100 by ones and by tens.

New Hampshire

1.NBT.B.2 — Understand that the two digits of a two-digit number represent amounts of tens and ones. Understand the following as special cases:
1.NBT.B.2.c — The numbers 10, 20, 30, 40, 50, 60, 70, 80, 90 refer to one, two, three, four, five, six, seven, eight, or nine tens (and 0 ones).
1.NBT.A.1 — Count to 120, starting at any number less than 120. In this range, read and write numerals and represent a number of objects with a written numeral.
1.NBT.B.2.a — 10 can be thought of as a bundle of ten ones — called a "ten."
1.NBT.C.5 — Given a two-digit number, mentally find 10 more or 10 less than the number, without having to count; explain the reasoning used.
K.CC.A.1 — Count to 100 by ones and by tens.

New Jersey

1.NBT.B.2 — Understand that the two digits of a two-digit number represent amounts of tens and ones. Understand the following as special cases: a. 10 can be thought of as a bundle of ten ones — called a “ten.” b. The numbers from 11 to 19 are composed of a ten and one, two, three, four, five, six, seven, eight, or nine ones. c. The numbers 10, 20, 30, 40, 50, 60, 70, 80, 90 refer to one, two, three, four, five, six, seven, eight, or nine tens (and 0 ones).
1.NBT.A.1 — Count to 120, starting at any number less than 120. In this range, read and write numerals and represent a number of objects with a written numeral.
1.NBT.C.5 — Given a two-digit number, mentally find 10 more or 10 less than the number, without having to count; explain the reasoning used.
K.CC.A.1 — Count to 100 by ones and by tens.

New Mexico

1.NBT.B.2 — Understand that the two digits of a two-digit number represent amounts of tens and ones. Understand the following as special cases:
1.NBT.B.2.c — The numbers 10, 20, 30, 40, 50, 60, 70, 80, 90 refer to one, two, three, four, five, six, seven, eight, or nine tens (and 0 ones).
1.NBT.A.1 — Count to 120, starting at any number less than 120. In this range, read and write numerals and represent a number of objects with a written numeral.
1.NBT.C.5 — Given a two-digit number, mentally find 10 more or 10 less than the number, without having to count; explain the reasoning used.
K.CC.A.1 — Count to 100 by ones and by tens.

New York

NY-1.NBT.2 — Understand that the two digits of a two-digit number represent amounts of tens and ones.
NY-1.NBT.2.c — Understand the numbers 10, 20, 30, 40, 50, 60, 70, 80, 90 refer to one, two, three, four, five, six, seven, eight, or nine tens (and 0 ones).
NY-1.NBT.1 — Count to 120, starting at any number less than 120. In this range, read and write numerals and represent a number of objects with a written numeral.
NY-1.NBT.5 — Given a two-digit number, mentally find 10 more or 10 less than the number, without having to count; explain the reasoning used.
NY-K.CC.1 — Count to 100 by ones and by tens.

North Carolina

NC.1.NBT.2 — Understand that the two digits of a two-digit number represent amounts of tens and ones. • Unitize by making a ten from a collection of ten ones. • Model the numbers from 11 to 19 as composed of a ten and one, two, three, four, five, six, seven, eight, or nine ones. • Demonstrate that the numbers 10, 20, 30, 40, 50, 60, 70, 80, 90 refer to one, two, three, four, five, six, seven, eight, or nine tens, with 0 ones.
NC.1.NBT.5 — Given a two-digit number, mentally find 10 more or 10 less than the number, without having to count; explain the reasoning used.
NC.1.NBT.7 — Read and write numerals, and represent a number of objects with a written numeral, to 100.
NC.K.CC.1 — Know number names and recognize patterns in the counting sequence by: • Counting to 100 by ones. • Counting to 100 by tens.

North Dakota

1.NO.NBT.1 — Demonstrate that the two digits of a two-digit number represent a composition of some tens and some ones.
1.NO.CC.3 — Represent several objects with a written numeral up to 120.
1.NO.CC.5 — Skip count forward and backward by 5s and 10s from multiples and recognize the patterns of up to 10 skip counts.
1.NO.NBT.5 — Mentally add or subtract 10 to or from a given two-digit number and explain the reasoning used.

Ohio

1.NBT.2 — Understand that the two digits of a two-digit number represent amounts of tens and ones. Understand the following as special cases: 10 can be thought of as a bundle of ten ones — called a “ten;” the numbers from 11 to 19 are composed of a ten and one, two, three, four, five, six, seven, eight, or nine ones; and the numbers 10, 20, 30, 40, 50, 60, 70, 80, 90 refer to one, two, three, four, five, six, seven, eight, or nine tens (and 0 ones).
1.NBT.1 — Count to 120, starting at any number less than 120. In this range, read and write numerals and represent a number of objects with a written numeral.
1.NBT.5 — Given a two-digit number, mentally find 10 more or 10 less than the number, without having to count; explain the reasoning used.
K.CC.1 — Count to 100 by ones and by tens.

Oklahoma

1.N.1.2 — Use concrete representations to describe whole numbers between 10 and 100 in terms of tens and ones. Know that 10 is equivalent to 10 ones and 100 is equivalent to 10 tens.
1.N.1.3 — Read, write, discuss, and represent whole numbers up to 100. Representations may include numerals, words, addition and subtraction, pictures, tally marks, number lines, and manipulatives.
1.N.1 — Count, compare, and represent whole numbers up to 100, with an emphasis on grouping in terms of tens and ones.
1.N.1.5 — Count forward, without objects, by multiples of 1s, 2s, 5s, and 10s, up to 100.
1.N.1.6 — Find a number that is 10 more or 10 less than a given number up to 100.

Oregon

1.NBT.A.1 — Count to 120, starting at any number less than 120. In this range, read and write numerals and represent a number of objects with a written numeral.
1.NBT.B.2 — Understand 10 as a bundle of ten ones and that the two digits of a two-digit number represent amounts of tens and ones.
1.NBT.C.5 — Without having to count, mentally find 10 more or 10 less than a given two-digit number and explain the reasoning used.
K.NCC.A.1 — Orally count to 100 by ones and by tens in sequential order.

Pennsylvania

CC.2.1.1.B.2 — Use place-value concepts to represent amounts of tens and ones and to compare two digit numbers.
CC.2.1.K.A.1 — Know number names and write and recite the count sequence.
CC.2.1.1.B.1 — Extend the counting sequence to read and write numerals to represent objects.

Rhode Island

1.NBT.A.1 — Count to 120, starting at any number less than 120. In this range, read and write numerals and represent a number of objects with a written numeral.
1.NBT.B.2 — Understand that the two digits of a two-digit number represent amounts of tens and ones. Understand the following as special cases:
1.NBT.B.2.c — The numbers 10, 20, 30, 40, 50, 60, 70, 80, 90 refer to one, two, three, four, five, six, seven, eight, or nine tens (and 0 ones).
1.NBT.C.5 — Given a two-digit number, mentally find 10 more or 10 less than the number, without having to count; explain the reasoning used. Identify arithmetic patterns of 10 more and 10 less than using strategies based on place value.
K.CC.A.1 — Count to 100 by ones and by tens.

South Carolina

1.NSBT.1c — Extend the number sequence to read, write and represent numbers to 100 using concrete models, standard form, and equations in expanded form.
1.NSBT.2a — Understand place value through 99 by demonstrating that ten ones can be thought of as a bundle (group) called a “ten”.
1.NSBT.2b — Understand place value through 99 by demonstrating that the tens digit in a two-digit number represents the number of tens and the ones digit represents the number of ones.
1.NSBT.1b — Extend the number sequence to count by fives and tens to 100, starting at any number.
1.NSBT.5 — Determine the number that is 10 more or 10 less than a given number through 99 and explain the reasoning verbally and with multiple representations, including concrete models.

South Dakota

1.NBT.B.2 — Understand that the two digits of a two-digit number represent amounts of tens and ones. Understand the following as special cases:
1.NBT.B.2.c — The numbers 10, 20, 30, 40, 50, 60, 70, 80, 90 refer to one, two, three, four, five, six, seven, eight, or nine tens (and 0 ones).
1.NBT.C.5 — Given a two-digit number, mentally find 10 more or 10 less than the number, without having to count; explain the reasoning used.
K.CC.A.1 — Count to 100 by ones and by tens.
1.NBT.B.2.a — 10 can be thought of as a bundle of ten ones — called a "ten."

Tennessee

1.NBT.B.3 — Know that the digits of a two-digit number represent groups of tens and ones (e.g., 39 can be represented as 39 ones, 2 tens and 19 ones, or 3 tens and 9 ones).
1.NBT.A.1 — Count to 120, by ones, twos, and fives starting at any multiple of that number. Count backward from 20. Read and write numbers to 120 and represent a quantity of objects with a written number.
1.NBT.C.6 — Mentally find 10 more or 10 less than a given two-digit number without having to count by ones and explain the reasoning used.
K.CC.A.1 — Count to 100 by ones, fives, and tens. Count backward from 10.

Texas

1.2B — use concrete and pictorial models to compose and decompose numbers up to 120 in more than one way as so many hundreds, so many tens, and so many ones;
1.2C — use objects, pictures, and expanded and standard forms to represent numbers up to 120;
1.5C — use relationships to determine the number that is 10 more and 10 less than a given number up to 120;
1.5B — skip count by twos, fives, and tens to determine the total number of objects up to 120 in a set;

Utah

1.NBT.2 — Understand that the two digits of a two-digit number represent amounts of tens and ones. Understand the following as special cases:
1.NBT.2.c — The numbers 10, 20, 30, 40, 50, 60, 70, 80, 90 refer to one, two, three, four, five, six, seven, eight, or nine tens (and 0 ones).
K.CC.1 — Count to 100 by ones and by tens.
1.NBT.1 — Count to 120, starting at any number less than 120. In this range, read and write numerals and represent a number of objects with a written numeral.
1.NBT.2.a — 10 can be thought of as a bundle of ten ones, called a "ten."
1.NBT.5 — Given a two-digit number, mentally find 10 more or 10 less than the number, without having to count; explain the reasoning used.

Vermont

1.NBT.B.2 — Understand that the two digits of a two-digit number represent amounts of tens and ones. Understand the following as special cases:
1.NBT.B.2.c — The numbers 10, 20, 30, 40, 50, 60, 70, 80, 90 refer to one, two, three, four, five, six, seven, eight, or nine tens (and 0 ones).
1.NBT.A.1 — Count to 120, starting at any number less than 120. In this range, read and write numerals and represent a number of objects with a written numeral.
1.NBT.B.2.a — 10 can be thought of as a bundle of ten ones — called a "ten."
1.NBT.C.5 — Given a two-digit number, mentally find 10 more or 10 less than the number, without having to count; explain the reasoning used.
K.CC.A.1 — Count to 100 by ones and by tens.

Virginia

1.NS.1e — Group a collection of up to 120 objects into tens and ones, and count to determine the total (e.g., 5 groups of ten and 6 ones is equal to 56 total objects).
K.NS.1j — Group a collection of up to 100 objects (e.g., counters, pennies, cubes) into sets of ten and count by tens to determine the total (e.g., there are 3 groups of ten and 6 leftovers, 36 total objects).
1.NS.1c — Represent forward counting patterns when counting by groups of 5 and groups of 10 up to 120 using a variety of tools (e.g., objects, coins, 120 chart).
1.NS.2d — Describe the number of groups of tens and ones when given a two-digit number and justify reasoning.

Washington

1.NBT.A.1 — Count to 120, starting at any number less than 120. In this range, read and write numerals and represent a number of objects with a written numeral.
1.NBT.B.2 — Understand that the two digits of a two-digit number represent amounts of tens and ones. Understand the following as special cases:
1.NBT.B.2.c — The numbers 10, 20, 30, 40, 50, 60, 70, 80, 90 refer to one, two, three, four, five, six, seven, eight, or nine tens (and 0 ones).
1.NBT.C.5 — Given a two-digit number, mentally find 10 more or 10 less than the number, without having to count; explain the reasoning used.
K.CC.A.1 — Count to 100 by ones and by tens.

Washington, D.C.

1.NBT.B.2 — Understand that the two digits of a two-digit number represent amounts of tens and ones. Understand the following as special cases:
1.NBT.B.2.c — The numbers 10, 20, 30, 40, 50, 60, 70, 80, 90 refer to one, two, three, four, five, six, seven, eight, or nine tens (and 0 ones).
1.NBT.A.1 — Count to 120, starting at any number less than 120. In this range, read and write numerals and represent a number of objects with a written numeral.
1.NBT.C.5 — Given a two-digit number, mentally find 10 more or 10 less than the number, without having to count; explain the reasoning used.
K.CC.A.1 — Count to 100 by ones and by tens.

West Virginia

M.1.10 — Understand the two digits of a two-digit number represent amounts of tens and ones. Understand the following as special cases: a. 10 can be thought of as a bundle of ten ones - called a "ten." (e.g., A group of ten pennies is equivalent to a dime.) b. The numbers from 11 to 19 are composed of a ten and one, two, three, four, five, six, seven, eight or nine ones. c. The numbers 10, 20, 30, 40, SO, 60, 70, 80, 90 refer to one, two, three, four, five, six, seven, eight or nine tens (and 0 ones).
M.1.13 — Given a two-digit number, mentally find 10 more or 10 less than the number, without having to count and explain the reasoning used.
M.1.9 — Count to 120, starting at any number less than 120. In this range, read and write numerals and represent a number of objects with a written numeral. Skip count to 120 by 2's. Skip count to 120 by S's and lO's.
M.K.1 — Count to 100 by ones and by tens.

Wisconsin

M.1.NBT.B.2 — Understand that the two digits of a two-digit number represent amounts of tens and ones. Understand the following as special cases: a. 10 can be thought of as a bundle of ten ones-called a "ten." b. The numbers from 11 to 19 are composed of a ten and one, two, three, four, five, six, seven, eight, or nine ones. c. The numbers 10, 20, 30, 40, 50, 60, 70, 80, 90 refer to one, two, three, four, five, six, seven, eight, or nine tens (and 0 ones).
M.K.CC.A.1 — Count to 100 by ones and by tens.
M.1.NBT.A.1 — Count to 120, starting at any number less than 120. In this range, read and write numerals and represent a number of objects with a written numeral.
M.1.NBT.C.5 — Given a two-digit number, mentally find 10 more or 10 less than the number, without having to count; explain the reasoning used.

Wyoming

1.NBT.F.2 — Understand that the two digits of a two-digit number represent amounts of tens and ones. Understand the following as special cases:
1.NBT.F.2.C — The numbers 10, 20, 30, 40, 50, 60, 70, 80, 90 refer to one, two, three, four, five, six, seven, eight, or nine tens (and 0 ones).
K.CC.A.1.A — Count to 100 by ones and by tens.
1.NBT.F.2.A — 10 can be thought of as a bundle of ten ones — called a “ten”.
1.NBT.G.5 — Given a two-digit number, mentally find 10 more or 10 less than the number, without having to count; explain the reasoning used .