Show:
Addition&Subtraction to 10
Addition to 20
Subtraction to 20
100

2+4=

6

100

6+6=

12

100

15-10=

5

200

5+5=

10

200

10+4=

14

200

14-7=

7

300

7-3=

4

300

7+8=

15

300

20-2=

18

400

3+6=

9
400

9+7=

16

400

17-9=

8

500

9-5=

4

500

12+5=

17

500

18-7=

11