What to notice
Read the answers down the list: 9, 18, 27, 36, 45, 54, 63, 72, 81, 90. The tens digit goes up by one each time while the ones digit goes down by one, and in each answer from 9 × 2 to 9 × 10 the two digits add to 9. 9 × 11 = 99 and 9 × 12 = 108 break the two-digit pattern, but their digits still add to a multiple of 9.
The tens digit is one less than the number you multiply by. For 9 × 6, one less than 6 is 5, and 5 needs 4 more to make 9, so the answer is 54. A child who learns this can find any 9s fact up to 9 × 10 in a couple of seconds.
The finger trick: hold up all ten fingers. For 9 × 4, fold down the fourth finger from the left. There are 3 fingers to the left of it and 6 to the right, so the answer is 36. It works from 9 × 1 to 9 × 10.
How to practise at home
- Teach the finger trick once, then let your child use it for as long as they need. Over time they stop folding fingers and simply see the answer.
- Practise the “one less, then make 9” rule aloud: “9 × 8: one less is 7, and 7 needs 2 to make 9, so 72.”
- Write the list in a column and let your child find the patterns. Ask what happens to the tens digits, and to the ones digits, as you go down.
- Use the drill on this page to see whether the facts come in under three seconds. A child still using fingers is usually slower, and that is fine as a stage.
Slips to watch for
- Swapping the digits, such as 45 for 9 × 6 or 36 for 9 × 7. Ask “one less than 6 is?” to fix the tens digit first.
- Using the finger trick for 9 × 11 or 9 × 12, where it does not work. Learn those two on their own: 99 and 108.
- Picking an answer that passes the digit check but belongs to another fact, such as 72 for 9 × 7. The digit sum says an answer is in the 9s, not which fact it is; the tens digit tells you that.