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Prime and Composite Numbers
Learn 11+ prime and composite numbers: factors, 1 and 2 as special cases, the sieve of Eratosthenes, quick tests for primes and prime puzzles.
This 11+ Maths lesson opens with an animated 9 min video in 12 short chapters. Your child then tries questions with a friendly coach, practises with questions that step up from Easy to Hard, and finishes with a review of the traps that caught them.
What the Prime and Composite Numbers video lesson covers
- Operation Prime Suspect
- Factors decide
- The special cases: 1 and 2
- The sieve of Eratosthenes
- Pause and try
- Quick tests
- Testing a number
- Case cracked
- Prime puzzles
- Primes in diagrams
- Pause and try
- Top agent tips
How every Prep4All video lesson works
STEP 1
Watch
An animated 6 to 10 minute lesson in short chapters, with captions and a mission to crack.
STEP 2
Try together
A friendly coach talks your child through three questions, with hints and a second try.
STEP 3
Practise
Ten questions that step up from Easy to Hard. Every wrong answer explains the trap behind it.
STEP 4
Review
See which traps caught them and jump straight back to the chapter that teaches it.