# Difference grid

Rule :

1. 2. A cross sign means one rectangle's number is the multiple of another one.
3. A line sign means one rectangle's number is adjacent to another one.

Example : The Puzzle :

The numbers must be from 1 to 11, and each number can appear max 3 times. • sorry for the missing rule – Jamal Senjaya Mar 13 '17 at 8:25

The only possible solution is 11 is the number that is only used twice

The position of the three 1s is immediately clear from the minus signs. This helps a lot because we can now always disregard 1s for multiplication clues. Next to the 5 there can only be a 2 or 3. If we use a 2 we would need at least four 3s to solve the grid (We would need another 3 below the 3 directly below the 1). This means a 3 has to be placed next to the 5. The left cell between the 6s can only have a 5 or 7, but a 7 would lead to a 1 next to it (and we already placed three of them). Next we take a look left to the 5. A 6 would lead to a 5 and 11 which are impossible differences. This leaves 4 as the only possibility. Above the top left 3 we need a multiple of 3 that has to appear another time. We already have three 3s and two 6s, so the only possibility is a 9. We have to place a 4 or 8 on both sides of the 2 at the bottom right. We already used two 4s, so we have to place an 8 which leads to a solved grid.

• if that answer is correct, there seem to be two minus-signs missing between the top-most 10 and its adjacing nines. – beetkeeper Mar 13 '17 at 10:48
• @beetkeeper Even though there are a lot of clues, it was never stated that all possible clues are shown. – w l Mar 13 '17 at 10:54
• @beetkeeper : Thanks, you are right, I miss it. – Jamal Senjaya Mar 13 '17 at 12:24
• @beetkeeper Also missing a minus for the starting 5 and the 6 to the right of it as well as the 5/6 in the top right. – David Starkey Mar 13 '17 at 13:29