Times table fluency
Lesson 6 of 10
Patterns in the nine times table
Objective. Use the digit-sum pattern to check nine times table facts.
The key idea
Every multiple of 9 up to 90 has digits that add to 9, and the tens digit is one less than the number you multiplied by.
Worked example
What is 7 × 9?
- 1Tens digit is one less than 7, so 6.
- 2Digits must add to 9, so the ones digit is 3.
Answer: 63
Practice
Each question comes with a picture and a listen button. Try it first, then reveal the answer.
Common mistake. Assuming the digit-sum trick works past 10 × 9 without adjustment.
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