In this puzzle, the answers a + f + h must add to [9]. As a + f = [4], therefore h = [9] - [4] = 5 As b + c + h = [18] and we now know h = 5, therefore b + c = [18] - 5 = 13. Hold that thought. b + c + d = [21], but that b + c = 13, so d = [21] - 13 = 8 As d + g = [10], therefore g = [10] - 8 = 2 Let's see where we've got to... Another way to start this puzzle is to look at [7] and [4]. [7] can only be made by adding 1 + 2 + 4 and [4] can only be made by adding 1 + 3. Therefore the 1 must go in the box which is common to both of them which is a. To complete [7], e = 4 and to complete [4], f = 3. To complete [12], c = 7 and finally b = 6. Here's the finished puzzle: You can see a harder example below. |