Prime and Composite Numbers — Interactive Lesson & Worksheet (Year 5–6)

Which fish belong in the prime pot? This 20-slide interactive lesson teaches prime and composite numbers, with a printable cut-and-paste worksheet included.

Mastering Prime and Composite Numbers in Year 5–6 Maths

Pupils learn the difference between prime and composite numbers, build on this to identify prime numbers in a given set, and identify all the prime numbers from 1 to 100. They learn that a prime number has exactly two factors, so 17 is prime because its only factors are 1 and 17, then follow the Sieve of Eratosthenes, crossing out multiples of 2, 3, 5 and 7 from a 1–100 grid to reveal every prime number, with the remaining crossed-out numbers being composite. The worksheet adds a cut-and-paste activity sorting numbers such as 37, 54 and 29 into prime or composite fish pots.

What’s Included

• 20-slide interactive lesson on prime and composite numbers
• Learning objectives on the difference between prime and composite numbers
• A step-by-step Sieve of Eratosthenes activity
• Selecting prime and composite numbers from a list
• A printable cut-and-paste worksheet with fish pot sorting

Key Benefits for Students

• Makes the sieve method for finding primes hands-on
• Builds a clear, memorable definition of prime and composite
• The worksheet extends practice beyond the screen
• Instant feedback on the interactive lesson questions

Why Teachers Love It

• No prep — ready for whole-class teaching on an interactive whiteboard
• The cut-and-paste worksheet suits a hands-on follow-up activity
• Self-marking questions support independent practice
• Suits teaching, revision and homework
• A dependable foundation before factors and HCF

Love this? You’ll love…

• Multiples Of A Number — Interactive Lesson (Year 5)
• Common Multiples — Interactive Lesson (Year 5)
• Divisibility Rules — Interactive Lesson (Ages 8–10)

A dependable addition to a Year 5–6 number topic, giving pupils a hands-on way to discover primes for themselves, on screen and on paper. Confident work with primes and composites supports factors, multiples and simplifying fractions.

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FAQs

What year group is this for?
Years 5–6 (ages 9–11), KS2.

Is a worksheet included?
Yes — a printable cut-and-paste activity.

Is it self-marking?
Yes, for the interactive lesson questions.