Multiplication and times tables · Usually met around P2
Commutative property: multiplying in either order
5 × 3 = 3 × 5: swap them, same answer.
How to do it
Method
5 × 3 = 3 × 5: swap them, same answer
3 rows of 5 = 5 rows of 3 = 15
Another way
Count both ways
5, 10, 15; 3, 6, 9, 12, 15
In full
Set things out in a rectangle: 3 rows of 5 is 3 fives = 15; looked at in columns, it is 5 columns of 3, 5 threes = 15. Nothing has changed, so 5 × 3 = 3 × 5. Swapping the two numbers in a multiplication never changes the answer. So use whichever you know: if 2 × 9 is unfamiliar, work out 9 × 2 = 18. Or count both ways to check: 5, 10, 15 and 3, 6, 9, 12, 15.
Worked examples
Have a go first, then open each one for the answer and the working.
Example 1
You know 7 × 3 = 21. 3 × 7 = □
Show the answer and working
Answer: 21
3 × 7 is 7 × 3 the other way round: 21.
Example 2
Which of these has the same answer as 4 × 6?
- A. 6 × 4
- B. 4 × 7
- C. 4 × 4
- D. 4 + 6
Choose the right answer
Show the answer and working
Answer: A. 6 × 4
Swapping keeps the answer: 6 × 4 = 4 × 6.
Example 3
2 × 6 = 6 × □ = □
Fill in each box
Show the answer and working
Answer: 2，12
6 × 2 is easier: count in 6s 2 times to get 12.
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