| 1 * 1 = 1 | 1 * 2 = 2 | 1 * 3 = 3 | 1 * 4 = 4 | 1 * 5 = 5 | 1 * 6 = 6 | 1 * 7 = 7 | 1 * 8 = 8 | 1 * 9 = 9 |
| 2 * 1 = 2 | 2 * 2 = 4 | 2 * 3 = 6 | 2 * 4 = 8 | 2 * 5 = 10 | 2 * 6 = 12 | 2 * 7 = 14 | 2 * 8 = 16 | 2 * 9 = 18 |
| 3 * 1 = 3 | 3 * 2 = 6 | 3 * 3 = 9 | 3 * 4 = 12 | 3 * 5 = 15 | 3 * 6 = 18 | 3 * 7 = 21 | 3 * 8 = 24 | 3 * 9 = 27 |
| 4 * 1 = 4 | 4 * 2 = 8 | 4 * 3 = 12 | 4 * 4 = 16 | 4 * 5 = 20 | 4 * 6 = 24 | 4 * 7 = 28 | 4 * 8 = 32 | 4 * 9 = 36 |
| 5 * 1 = 5 | 5 * 2 = 10 | 5 * 3 = 15 | 5 * 4 = 20 | 5 * 5 = 25 | 5 * 6 = 30 | 5 * 7 = 35 | 5 * 8 = 40 | 5 * 9 = 45 |
| 6 * 1 = 6 | 6 * 2 = 12 | 6 * 3 = 18 | 6 * 4 = 24 | 6 * 5 = 30 | 6 * 6 = 36 | 6 * 7 = 42 | 6 * 8 = 48 | 6 * 9 = 54 |
| 7 * 1 = 7 | 7 * 2 = 14 | 7 * 3 = 21 | 7 * 4 = 28 | 7 * 5 = 35 | 7 * 6 = 42 | 7 * 7 = 49 | 7 * 8 = 56 | 7 * 9 = 63 |
| 8 * 1 = 8 | 8 * 2 = 16 | 8 * 3 = 24 | 8 * 4 = 32 | 8 * 5 = 40 | 8 * 6 = 48 | 8 * 7 = 56 | 8 * 8 = 64 | 8 * 9 = 72 |
| 9 * 1 = 9 | 9 * 2 = 18 | 9 * 3 = 27 | 9 * 4 = 36 | 9 * 5 = 45 | 9 * 6 = 54 | 9 * 7 = 63 | 9 * 8 = 72 | 9 * 9 = 81 |
ref: https://forums.phpfreaks.com/topic/250229-php-multiplication-tables/