00:00:00
10 + 10 =
- 20
5 + 11 =
- 16
12 + 6 =
- 18
7 + 7 =
- 14
5 – 2 =
- 3
10 – 8 =
- 2
15 – 6 =
- 9
20 – 12 =
- 8
50 – 30 =
- 20