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Swim Meet Mental Math: Make a Ten and Doubles worksheet preview

Worksheet

Swim Meet Mental Math: Make a Ten and Doubles

Grade 2 mental math within 20 at a swim meet: make a ten, use doubles and near doubles, and think addition to subtract.

Grade 2MathInteractive · Printable

Aligned to2.OA.B.2

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What’s included

  • Single worksheet
  • Auto-graded online
  • 1 Common Core standard
  • Printable answer key
  • 13 questions
  • Classroom-ready

Details

Format
Interactive · Printable
Grade
Grade 2
Subject
Math
Question types
Fill in the blank, Multiple choice, Matching, Circle the answer, Sorting, Short answer

About this worksheet

What students practice

  • Students add within 20 by making a ten and by using doubles and near doubles.
  • Students subtract within 20 by getting to ten first or by thinking of an addition fact.
  • Students explain why a make-a-ten strategy gives the same sum.

How to use

Use after teaching make-a-ten and doubles strategies. Have students say each strategy step out loud for the first few problems, then finish the rest in their heads.

Curriculum

Common Core standard covered

2.OA.B.2

Add and subtract within 20 fluently using mental strategies.

Preview

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Swim Meet Mental Math: Make a Ten and Doubles

Use make-a-ten, doubles, and think-addition to add and subtract within 20 in your head.

Make a ten

Get to 10 first. Then add or take away the rest.

1.
Lane 1 has 8 swimmers warming up. 5 more swimmers jump in. Break apart the 5 to make a ten.

8 + 5 = 10 +   =   swimmers

2.
Coach Rosa has 9 kickboards. She gets 6 more. Break apart the 6 to make a ten.

9 + 6 = 10 +   =   kickboards

3.
The ten frame shows 7 swim caps in a basket. Use it to find 7 + 6.

7 +   = 10
7 + 6 =  

4.
There are 14 towels on the bench. 6 swimmers each take one. Take away 4 to get to 10 first. Then take away the rest.

14 − 6 = 14 − 4 −   =   towels

Doubles and near doubles

Use doubles facts you know to solve facts you are not sure of.

5.
Match each doubles fact to its sum.
  1. 6 + 6
  2. 8 + 8
  3. 9 + 9
  4. 7 + 7
  1. A. 16
  2. B. 14
  3. C. 18
  4. D. 12
6.
Ava swam 7 laps on Monday and 8 laps on Tuesday. Which way of thinking gives the right answer for 7 + 8?
  • A. 8 + 8 = 16, so 7 + 8 is 1 more.
  • B. 7 + 7 = 14, so 7 + 8 is 1 less.
  • C. 7 + 7 = 14, so 7 + 8 is 1 more.
  • D. 6 + 6 = 12, so 7 + 8 is 2 more.
7.
Maya dove for 6 rings. Then she dove for 7 more rings. Use the double 6 + 6 to help.

6 + 7 = 6 + 6 +   =   rings

8.
Use each doubles fact to subtract.

8 + 8 = 16, so 16 − 8 =  
9 + 9 = 18, so 18 − 9 =  

Fast facts at the pool

Solve each fact in your head. Pick any strategy that helps.

9.
Think addition to subtract. What do you add to 5 to get 13?

5 +   = 13, so 13 − 5 =  

10.
Each swimmer's lane card shows a fact. Circle every fact that equals 9.

17 − 84 + 515 − 712 − 36 + 418 − 83 + 611 − 3

11.
Solve each fact. Sort it by its answer.
6 + 413 − 48 + 517 − 79 + 315 − 8
Less than 10Equal to 10More than 10
12.
There are 16 swimmers in the pool. 9 swimmers climb out. How many swimmers are still in the pool?
  • A. 8
  • B. 7
  • C. 6
  • D. 25
13.
Jamal says 9 + 7 has the same sum as 10 + 6. Is he right? Explain how you know.

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