Grade 3 · Unit 1: Number and place value

Factors and multiples

How are numbers related?

Chairs set out in rows.

Arranging chairs

24 chairs can be set out in rows in many ways. 2 rows of 12, 3 rows of 8, 4 rows of 6… Each way shows a factor pair of 24.

Factor pairs

3 and 8 are factors of 24. All factor pairs of 24: 1 × 24, 2 × 12, 3 × 8, 4 × 6. So the factors are 1, 2, 3, 4, 6, 8, 12, 24.

Multiples

Multiples of 6 are in the 6 times table. They go on forever. 24 is a multiple of 6 AND of 8.

Common multiples

Some numbers are multiples of two numbers. 12 is the smallest multiple of both 3 and 4. This helps with fractions later.

Square numbers

1, 4, 9, 16, 25 … make square arrays. Each square grows by adding an L-shape of dots: +3, +5, +7, +9. A number that divides another exactly is a divisor: 4 is a divisor of 16.

Quick tests

Does 340 divide by 2? It ends in 0: yes. Does 345 divide by 5? It ends in 5: yes. Does 345 divide by 10? No – it does not end in 0.

What I learnt