21 = 3 * 5 + 6, that sounds easy. But unfortunately 3, 5 and 6 are not lying close to each other in a field of 40 numbers. So there must be another combination of three numbers, that equals 21. Beware of your time! Finally, there it is: 4 * 6 - 3 also equals 21 and all there numbers are in a diagonal. Go on! The next exercise is already shown.
How to play Num3ers?
A game from: Andreas Lindenberg