| Question | Answer |
| 2 + 7 = _ + 5 | 4 | 10 - 5 = 3 + _ | 2 | 13 - 5 = 18 - _ | 10 | 19 + _ = 10 + 10 | 1 | 16 - 6 = 20 - _ | 10 | 8 + _ = 4 + 4 | 0 | 16 - _ = 10 - 2 | 8 | 3 + _ = 10 - _ | 4 | 13 - 7 = _ + 3 | 3 | 0 + 18 = 9 + _ | 9 | 7 + _ = 20 - _ | 13 | 18 - _ = 12 + 6 | 0 | 13 - _ = 5 | 8 | 20 - _ = 8 | 12 | 13 + _ = 20 | 7 | _ + 11 = 16 | 5 | _ + 8 = 19 | 11 | _ + 3 = 15 | 12 | 2 + _ = 16 | 14 | _ + 5 = 20 | 15 |
