Free Year 7 Prime, composite, square numbers Practice | Skillo

Question 1 — Easy

Priya is sorting numbers for a maths activity at school. She needs to find all the prime numbers from this list: 51, 53, 57, 59. Which numbers from the list are both prime?

Answer: 53 and 59 are both prime because their only factors are 1 and themselves. 51 is divisible by 3 (51 = 3 × 17), and 57 is also divisible by 3 (57 = 3 × 19), making both composite numbers.

Question 2 — Medium

Priya is arranging 36 square tiles into equal rows to make a square pattern on her kitchen floor. Which statement about 36 is correct?

Answer: 36 is a square number because it equals 6 × 6, meaning it can be arranged into a perfect square. It is not prime — it has many factors including 1, 2, 3, 4, 6, 9, 12, 18 and 36, so options A and C are both wrong. Having more than two factors makes a number composite, not 'not a square number', so D is also incorrect.

Question 3 — Hard

Priya is organising chairs for a school assembly. She wants to arrange exactly 47 chairs into equal rows with no chairs left over. Which of the following statements is true about the number 47?

Answer: 47 is prime because its only factors are 1 and 47, meaning it cannot be arranged into equal rows other than one row of 47 — making option B correct. Option D is wrong because being odd does not make a number composite; odd numbers can still be prime.