Number Sum
The following grid of size 5x5 is partially complete with whole numbers from 1 to 7.
The sum of each row and column is shown on the edges of the grid.
Fill in the missing numbers to complete the grid.
| 20 | 23 | 18 | 13 | 21 | |
| 20 | 6 | 4 | |||
| 18 | 7 | ||||
| 13 | 3 | ||||
| 27 | 6 | ||||
| 17 | 7 | 1 |