how many pairs of whole numbers have a sum of 40
For thewriter, there are 201.1
2.2
3.3
4.4
5.5
6.6
7.7
8.8
9.9
10.10
11.11
12.12
13.13
14.14
15.15
16.16
17.17
18.18
19.19
20.20