Grade 4 · Unit 1: Number and place value

Number properties

Odd, even, prime or square?

Number detectives

Numbers have properties, just like shapes. Some are odd, some even, some prime, some square. Knowing properties helps you calculate quickly.

Prime and composite

A prime number has exactly 2 factors: 7 = 1 × 7 only. A composite number has more: 12 = 1 × 12, 2 × 6, 3 × 4. 1 is neither prime nor composite.

Square numbers

Square numbers make square arrays. 1, 4, 9, 16, 25, 36, 49, 64, 81, 100. We can write 4 × 4 as 4².

Divisibility tests

Is 345 divisible by 3? 3 + 4 + 5 = 12, and 12 ÷ 3 = 4. Yes! Is 345 divisible by 5? It ends in 5. Yes. Is it divisible by 2? It ends in 5 (odd). No.

What I learnt

• I can identify prime and composite numbers.
• I know square numbers to 100.
• I can use divisibility tests.