| Chap. | Easy | Medium | Hard |
| 1 | 4, 7, 14, 23, 32, 33, 38 | 19,21,35,43,45,46 | 66, 72 |
| 2 | 3, 5, 18, 21, 25, 29, 34, 39 | 4, 8, 9, 12, 13, 22, 31, 32 | 49, 55 |
| 3 | 1, 5, 9, 23, 25, 27, 28, 34 | 3, 6, 11, 12, 13, 15, 30, 33 | 16, 47, 50 |
| 4 | 2, 3, 7, 9, 11, 13, 14, 26 | 4, 8, 17, 22, 24, 27, 28, 30 | 44, 47 |
| 5 | 1, 2, 8, 16, 23, 31, 32 | 9, 10, 11, 12, 13, 19, 21 | 44, 45 |
| 6 | 1, 2, 4, 5, 7, 11, 15, 33 | 9, 12, 17, 27, 29, 34, 38, 42 | 14, 51 |
| 7 | 7, 19, 24, 32, 35, 36, 39 | 2, 5, 9, 10, 16, 21, 23, 25, 28 | 14, 15, 53 |
| 8 | 1, 4, 6, 13, 14, 19, 29, 37 | 7, 9, 16, 20, 21, 27, 33, 48 | 51, 59 |
| 10 | 1, 9, 14, 16, 20, 22, 42, 45 | 6, 8, 23, 31, 32, 41, 49, 54 | 63, 73, 76 |
| 15 | 2, 3, 4, 10, 15, 18, 19, 30 | 11, 12, 21, 23, 25, 34 | 33 |