# Maths KS2: Prime Suspects 2

**This clip introduces prime numbers, composite numbers and factors.**

We state that the number "1" is neither prime nor composite. The idea of factor pairs is introduced.

We look at how to decide whether a natural number is prime or composite by looking for proper factors.

The importance of being methodical is emphasised.

The clip ends with a square roots sketch illustrating the relationship between square numbers and their square roots.

This clip is from the series Kick Sum Maths.

*Teacher Notes*

*This clip can form an introduction to prime and composite numbers, and lead to discussion of ways to speed up identification of primes/composites, for example, using divisibility tests.*

*The sketch at the end of the clip can serve as a discussion starter about square numbers and square roots.*

*Curriculum Notes*

*These clips could be used for teaching Maths at KS2 or at a beginner level in England, Wales and Northern Ireland and 1st and 2nd Level in Scotland.*