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1st grade · Math · Unit 9 of 14

Numbers to 100

Tens, ones and big numbers!

What your child practices

Reading and building numbers to 100 with tens and ones, comparing them, and seeing that two names can mean the same amount.

Arizona Academic Standards learning standard: 1.NBT.A.1; 1.NBT.B.2; 1.NBT.B.3 · counting to 120, tens and ones, and comparing two-digit numbers

How we explain it

Children can open this short lesson before they practice.

  1. A 2-digit number has tens and ones.
  2. 10 tens make 100.
  3. Compare the tens first. More tens means bigger.

Example: Which is less: 39 or 42? Tens: 3 tens and 4 tens. 3 tens is less. So 39 is less. Answer: 39

Numbers to 100 in Arizona

In the Arizona Academic Standards, this is unit 9 of 14 in 1st grade Math, after Data & Graphs and before Count It Up.

Gradelings describes a child's practice on this unit as Beginning, Approaching, Meeting or Exceeding (Four practice steps). That reflects practice, not a report-card mark: the teacher decides the mark.

Source: Arizona Department of Education

Sample questions

A taste of this unit. In the app, questions change every time and get easier or harder to match your child.

  1. Question 1

    Tap the numbers from smallest to biggest.

    • 29
    • 50
    • 36
    • 27

  2. Question 2

    Is 14 equal to 1 tens and 4 ones?

    • No, not equal (≠)
    • Yes, equal (=)

  3. Question 3

    Which number is less: 75 or 46?

    • 75
    • 46

  4. Question 4

    What number is shown?

    • 48
    • 44
    • 38

  5. Question 5

    Build the number 70.

    Build it with tens rods and ones cubes.

  6. Question 6

    How many tens make 20?

    • 1
    • 4
    • 2

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