Show:
Addition
Subtraction
Addition or Subtraction
10

1 +  3 

4

10

5- 3

2

10

11 + 1

12

20

5 + 6

11

20

8 - 4

4

20

10 - 1

9

30

8 + 4

12

30

10 - 2 

8

30

20 + 2

22

40

10  +  3

13

40
10 - 7

3

40

6- 3

3

50

15 + 4

19

50

15 - 5 

10

50

20 - 20 

0