Mental Math
3 sec. addition
3 sec. subtraction
Say 10 Way
10 more, 10 less
100

2 tens + 5 tens=

7 tens

100

8 + 7=

15

100

25-10=

15

100

342

3 hundreds

4 tens

2 ones

100

Ten less than 38 is____

28

200

34 tens - 1 tens=

24 tens

200

20 + 4=

24

200

16-4=

12

200

695

6 hundreds

9 tens

5 ones

200

Ten more than 96 is _____

106

300

660 - 400=

260

300

13 + 6=

19

300

20-6=

14

300

7 hundreds

7 tens

4 ones

774

300

Ten less than 58 is _____

48

400

330 - 130=

200

400

7 + 9=

16

400

30-30=

0

400

9 tens

4 hundreds

2 ones

492

400

Ten more than 148 is ________

158

500

600 + 40 + 5=

645

500

10 + 12=

22

500

52-42=

10

500

5 ones

3 tens

8 hundreds

835

500

Ten less than 190 is _____

180

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