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Grade 3 · Math · Unit 2 of 13

Facts to 20

Quick adding and subtracting

What your child practises

Building fast, flexible recall of addition and subtraction facts to 20 with strategies like making ten, near doubles, fact families and thinking addition to subtract.

Prince Edward Island Curriculum curriculum outcome: N10 · adding and subtracting facts to 18 with mental strategies such as doubles and making 10

How we explain it

Children can open this short lesson before they practise.

  1. Use doubles you know: 5 + 5 = 10.
  2. Near doubles: 5 + 6 is one more than 5 + 5.
  3. For subtraction, think of the missing addend: 12 − 6 is 6 + ☐ = 12.

Example: 5 + 5 = 10. So what is 5 + 6? 6 is one more than 5. So the answer is one more than 10: 11. Answer: 11

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

    8 + 8 = 16. So what is 8 + 9?

    8 + 9 = ?

    • 15
    • 17
    • 16
    • 19

  2. Question 2

    Ravi has 12 stickers and gives 7 to a friend. How many stickers are left?

    ⭐

    answer box

  3. Question 3

    Make a ten! What number goes in the box?

    7 + 8 = 10 +

    • 6
    • 8
    • 5
    • 4

  4. Question 4

    What is 9 + 8?

    9 + 8 = ?

    answer box

  5. Question 5

    Which fact is in the same family as 6 + 9 = 15?

    6 + 9 = 15

    • 15 + 6 = 21
    • 9 − 6 = 3
    • 9 + 6 = 15
    • 15 − 7 = 8

  6. Question 6

    What is 12 − 7?

    12 − 7 = ?

    answer box

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