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The teen numbers

CONCEPTUAL
Mathematics›Number Representation & Place Value|Ages 5—7|ID: mt_xmmgAzxe5j

Understand that the teen numbers (11–19) are composed of ten ones and some further ones (early place value)

Mastery Evidence

  • Compose 14 as a group of ten and four ones using objects
  • Decompose 17 into 10 + 7 and record as an equation
  • Explain that 13 is 'one ten and three ones'

Assessment Prompt

“If [child] has 14 building blocks, can they see it as one full tower of 10 and 4 left over — understanding 'teen' numbers as ten-and-some-more?”

Curriculum Standards2 alignments

1.NBT.2.bCommon Core State Standards for Mathematics
Composition of numbers 11 to 19

The numbers from 11 to 19 are composed of a ten and one, two, three, four, five, six, seven, eight, or nine ones.

NBT
K.NBT.1Common Core State Standards for Mathematics
Compose and Decompose Numbers 11-19

Compose and decompose numbers from 11 to 19 into ten ones and some further ones, e.g., by using objects or drawings, and record each composition or decomposition by a drawing or equation (e.g., 18 = 10 + 8); understand that these numbers are composed of ten ones and one, two, three, four, five, six, seven, eight, or nine ones.

Number and Operations in Base Ten

Prerequisites2

Show full prerequisite tree
  • How Many in Total? hard

    Understanding tens-and-ones composition requires cardinality — knowing numbers represent quantities

    • One-to-one counting hard

      Cardinality principle builds on one-to-one correspondence — you must count correctly to know the last number tells 'how many'

  • Reading and writing numbers to 20 hard

    Composing/decomposing teen numbers requires reading and writing those numerals

    • How Many in Total? hard

      Reading/writing numerals 0–20 requires understanding that numerals represent quantities (cardinality)

      • One-to-one counting hard

        Cardinality principle builds on one-to-one correspondence — you must count correctly to know the last number tells 'how many'

    • Writing digits 0-9 hard

      Writing numerals requires the motor skill of forming digits 0-9 (taught in English handwriting)

Unlocks3