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2nd grade · Math · Unit 2 of 18

Facts to 20

Add and take away

What your child practices

Fluent facts to 20 using strategies like making ten and thinking addition to subtract.

New York State Learning Standards learning standard: NY-2.OA.2 · fluently adding and subtracting within 20 with mental strategies

How we explain it

Children can open this short lesson before they practice.

  1. Use 10 as a stepping stone.
  2. Break one number to make a 10 with the other.
  3. Then add what is left over.

Example: 8 + 5 = ? 8 needs 2 more to make 10. Take 2 from 5. That leaves 3. 10 + 3 = 13. Answer: 13

Facts to 20 in New York

In the New York State Learning Standards, this is unit 2 of 18 in 2nd grade Math, after Bigger or Smaller and before Adding to 100.

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: New York State Education Department (NYSED)

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

    What is 10 − 4?

    10 − 4 = ?

    • 6
    • 3
    • 10

  2. Question 2

    What is 19 − 8?

    19 − 8 = ?

    • 16
    • 11
    • 9

  3. Question 3

    What is 15 − 3?

    15 − 3 = ?

    • 18
    • 12
    • 16

  4. Question 4

    What number is missing?

    8 + = 11

    • 3
    • 4
    • 7

  5. Question 5

    What is 7 + 7?

    • 14
    • 16
    • 17

  6. Question 6

    What is 7 + 6?

    7 + 6 = ?

    • 13
    • 12
    • 16

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