Write the missing numbers that add up to 20. The first one is done for you.
7 + 13 = 20
8 + 12 = 20
6 + 14 = 20
17 + 3 = 20
12 + 8 = 20
5 + 15 = 20
4 + 16 = 20
19 + 1 = 20
11 + 9 = 20
15 + 5 = 20
10 + 10 = 20
14 + 6 = 20
0 + 20 = 20
16 + 4 = 20
2 + 18 = 20