Adding and Subtracting single digit numbers

Adding up to 10

100

1+8

9

200

9+1

10

300

4+7

11

400

2+6

8

500

5+5

10

subtracting up to 10

100

9-2

7

200

10 - 3

7

300

6 - 2

4

400

8 - 7

1

500

10 - 5

5

adding up to 20

100

11 + 3

14

200

12 + 4

16

300

14 + 4

18

400

11 + 8

19

500

13 + 5

18