Grouping numbers to add · seed 1 · A4, ink-friendly. The answer key prints on its own page for grown-ups.

Grouping numbers to add

Mathematics · Addition & Subtraction · ages 6-7
Name ______________________   Date ____________

  1. To add 4 + 6 + 2, which pair makes a nice round number?

    • 4 and 6
    • 6 and 2
    • 4 and 2

  2. Is this true? (1 + 2) + 3 gives the same total as 1 + (2 + 3).

    Circle one:   True   False

  3. Solve 2 + 6 + 4 by adding the friendly pair first. What is the total?

    Answer: ______________

  4. When you add three numbers, you always have to add the first two before adding the third.

    Circle one:   True   False

  5. Which shows a different way to group the sum 4 + 1 + 9?

    • (4 + 1) + 9
    • 4 + (1 + 9)
    • 1 + 4 + 9 in a new order

  6. Add 5 + 3 + 7. Group the friendly pair first. What is the total?

    Answer: ______________

  7. Which is the easiest first step for 7 + 8 + 2?

    • Add 7 + 8 first
    • Add 8 + 2 first
    • Add 7 + 2 first

  8. Add 5 + 8 + 5 by grouping the two 5s first. What is the total?

    Answer: ______________

  9. Tom says 2 + 9 + 1 must be solved left to right: 2 + 9 first, then plus 1. Is Tom right?

    • No, three numbers cannot be added at all
    • Yes, that is the only way
    • No, he can add 9 and 1 first instead

  10. Which grouping of 8 + 5 + 5 makes the adding easiest?

    • (8 + 5) + 5
    • 8 + (5 + 5)
    • (5 + 5) + 8 and 8 + (5 + 5) are both easy
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Answer key

For grown-ups. Fold this page away before handing over the rest.

Grouping numbers to add W1-mt_T76hKqXf0z-s1

  1. 4 and 6 · 4 + 6 = 10, an easy number. Then add 2 to get 12.
  2. True · Both sides add up to 6. Moving the parentheses does not change the total.
  3. 12 · Group 6 + 4 to make 10, then add 2 to get 12.
  4. False · You can add any two numbers first. The total stays the same no matter which pair you start with.
  5. 4 + (1 + 9) · Putting parentheses around 1 + 9 changes the grouping, not the total. Both ways equal 14.
  6. 15 · Group 3 + 7 to make 10, then add 5 to get 15.
  7. Add 8 + 2 first · 8 + 2 makes 10, and adding 7 + 10 is quick and simple.
  8. 18 · 5 + 5 = 10, then 10 + 8 = 18.
  9. No, he can add 9 and 1 first instead · 9 + 1 = 10 is an easier first step. Grouping any two numbers first still gives 12.
  10. (5 + 5) + 8 and 8 + (5 + 5) are both easy · Both groupings put the two 5s together to make 10, and 10 + 8 is simple.
Worksheet · LightMySky