Fill in the missing numbers with the digits 1 to 9. A diamond shape in the middle means that the four numbers around it add to 20.

Each uses a different way to add to 20, if there is already 1 + 3 + 7 + 9, then there will not be another using the digits 1, 3, 7 and 9 (in any order).

The same digit isn't allowed to touch, even diagonally.

Puzzle Copyright © Elliott Line
This puzzle appeared in Mensa's EnigmaSig (195.08) and is used with permission.