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1st Grade · Math · Domain guide

Number & Operations in Base Ten in 1st Grade (1.NBT)1.NBT Standards

Short answer. Place value is the big idea of 1st grade math, and 1.NBT is where it lives. Your child learns that the 4 in 47 isn't a four at all, it's four tens. From that one insight comes counting to 120 from any starting point, comparing two-digit numbers with the >, =, and < symbols, and finding 10 more or 10 less in her head without counting.

The domain runs in three clusters. 1.NBT.A extends the counting sequence to 120. 1.NBT.B builds the tens-and-ones understanding itself, including seeing 10 as a bundle of ten ones. 1.NBT.C puts it to work: adding within 100, adding a two-digit number and a multiple of 10, and subtracting multiples of 10. Expect homework with base-ten drawings, sticks and dots, before any stacked-up arithmetic appears.

Grade
1st Grade
Learning level
Subject
Math
Skill area
Standards
6
Skills in this domain
Clusters
3
Related skill groups

Complete domain directory

Every 1.NBT standard, in order

Open a code for the official wording, a plain-English answer, what the skill can look like at home, and simple activities. The list below follows the Common Core sequence.

01
Cluster

Extend the counting sequence.

1 standard

  1. 1.NBT.A.1Count to 120 From Any Starting Number (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.

02
Cluster

Understand place value.

2 standards

  1. 1.NBT.B.2Understanding Tens and Ones in Two-Digit Numbers (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:

  2. 1.NBT.B.3Comparing Two-Digit Numbers With >, =, and < (1.NBT.B.3)

    Compare two two-digit numbers based on meanings of the tens and ones digits, recording the results of comparisons with the symbols >, =, and <.

03
Cluster

Use place value understanding and properties of operations to add and subtract.

3 standards

  1. 1.NBT.C.4Adding Within 100 Using Place Value (1.NBT.C.4)

    Add within 100, including adding a two-digit number and a one-digit number, and adding a two-digit number and a multiple of 10, 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 and explain the reasoning used. Understand that in adding two-digit numbers, one adds tens and tens, ones and ones; and sometimes it is necessary to compose a ten.

  2. 1.NBT.C.5Finding 10 More or 10 Less in Your Head (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.

  3. 1.NBT.C.6Subtracting Tens From Tens, 10 Through 90 (1.NBT.C.6)

    Subtract multiples of 10 in the range 10-90 from multiples of 10 in the range 10-90 (positive or zero differences), 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 and explain the reasoning used.

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More than a standards list

Use the framework guide for context, the learning hub for explanations, or printable practice when your child is ready to work on a skill.

1.NBT is part of the Common Core State Standards. Whizki keeps official wording separate from parent-friendly explanations.

All Common Core parent guides

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