Multiplication Patterns – Spot the Rules
Multiplication tables are full of patterns. Spotting them helps you check answers, spot errors, and remember facts without rote memorisation.
The 2 Times Table – Always Even
Every multiple of 2 is even (ends in 0, 2, 4, 6, 8).
2, 4, 6, 8, 10, 12, 14, 16, 18, 20...
The 5 Times Table – Ends in 0 or 5
5, 10, 15, 20, 25, 30, 35, 40...
The 9 Times Table – Digit Sum Always 9
9, 18 (1+8=9), 27 (2+7=9), 36 (3+6=9), 45 (4+5=9), 54...
Also: the tens digit increases by 1 and the ones digit decreases by 1 each time.
The 11 Times Table – Mirror Digits (up to 99)
11, 22, 33, 44, 55, 66, 77, 88, 99
Even and Odd Products
| Factors | Product |
|---|---|
| Even × Even | Always Even |
| Even × Odd | Always Even |
| Odd × Odd | Always Odd |
Square Numbers
When you multiply a number by itself, you get a square number: 1, 4, 9, 16, 25, 36, 49, 64, 81, 100.
Key Takeaways
- Patterns help you check answers without recalculating.
- The 9-times digit sum rule is one of the most useful quick checks.
- All multiples of 2, 4, 6, 8, 10 are even.
- Square numbers form a diagonal on the multiplication grid.
Practice Questions
- Without calculating, is 7 × 9 odd or even?
- Use the digit sum rule to check: is 54 a multiple of 9?
- List the first ten square numbers.
- What pattern do you notice in the last digits of multiples of 4?
- Is 375 a multiple of 5? How do you know immediately?