A free book of 66 cross numbers (here) originally created with X-figure PC program (now available as an app from here). Most of the answers are cross-referenced to other answers in the cross number puzzle, this means that it requires logical thinking and perseverance. Wherever answers are not cross-referenced, the starting point for the solution, they come from one of several categories:
- time conversions
- metric conversions
- miscellaneous conversions
You will need to ensure that pupils know about these conversions (especially the meaning of gross, score and decade). Later on pupils will need to know about primes, squares and cubes. Finally, comes the introduction of factors and multiples.
Additional Spreadsheet
Additional Spreadsheet available (here) for puzzles 3, 6 and 9. Lets you put answers into the spreadsheet and once completed tells you whether it is correct or not. Answer can also be shown.
| Cross Number Puzzle | Grid Size | Difficulty Factor |
| 1 to 14 | 7 by 7 | Easy |
| 15 to 28 | 8 by 8 | Simple |
| 29 to 42 | 9 by 9 | Straightforward |
| 43 to 48 | 9 by 9 (5 fig nos) | Hard |
| 49 to 53 | 11 by 11 | Harder still |
| 54 | 11 by 11 | Very hard |
| 55 to 58 | 12 by 12 | Difficult |
| 59 and 60 | 12 by 12 | Very difficult |
| 61 to 64 | 13 by 13 | Extremely hard |
| 65 and 66 | 13 by 13 | Teacher’s challenge |
