2024年3月13日发(作者：杭州2022中考数学试卷)

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Practice 1 Mental Addition

Add mentally.

First add the ones.

Then add the ones to the tens.

Example

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Mental Math Strategies

14 + 3 =

17

10

1.

4

2. 12 + 4 = 15 + 2 =

3. 35 + 1 = 4. 23 + 5 =

5. 22 + 7 = 6. 31 + 8 =

7. 6 + 32 = 8. 5 + 34 =

Lesson 1Mental Addition

99

Add mentally.

First add the tens.

Then add the tens to the ones.

Example

13 + 10 =

23

3

9.

10

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18 + 10 = 10. 11 + 20 =

11. 12 + 10 = 12. 14 + 20 =

13. 16 + 10 = 14. 20 + 19 =

15. 10 + 17 = 16. 20 + 13 =

17. 10 + 14 = 18. 20 + 16 =

100

Chapter 14Mental Math Strategies


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