CCSS.Math.Content.1.NBT.B

Math1st GradeNumber and Operations in Base Ten

The standard

Understand place value.

Common Core State Standards for Mathematics

What this standard means

Students need to see two-digit numbers as tens and ones, not just a string of digits. They should build numbers with ten-sticks and ones, say what each digit means, count by tens and ones, and compare numbers using place value.

Mastery looks like a student building 47 as 4 tens and 7 ones, explaining that 52 is greater than 49 because 5 tens beats 4 tens, and regrouping ten ones as one ten. Common trouble spots are reading 30 as 3 ones, comparing only the ones digit, and counting after a decade number like 59 or 70.

Ways to teach it

  • Have students build number cards with base-ten blocks, then trade ten ones for one ten whenever they can.
  • Ask, “Which is greater, 64 or 46, and how do you know without counting all?”
  • Show 38 with blocks and ask students to write the number, draw it, and label tens and ones.
  • Use classroom collections, like 27 crayons, to bundle groups of ten and count leftovers as ones.

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Related standards

Standard text verified against corestandards.org on July 10, 2026.

Page updated July 10, 2026.

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