Why does my child write 60 = 2 × 3 × 5?
Your child leaves out a prime factor that repeats, such as 60 = 2 × 3 × 5.
Why children do it
Children list each prime that goes into 60, but each one only once, as if naming them. Prime factors have to multiply back to the number, and 2 × 3 × 5 is only 30, so a 2 is missing: 60 is 2 × 2 × 3 × 5.
How to help at home
Ask them to multiply their primes back together: they should get the number they started with.
The right way
Write as a product of prime factors: 60
- 60 = 6 × 10Split 60 into any two factors.
- 60 = 2 × 3 × 2 × 5Split 6 and 10 into primes.
- 2² × 3 × 5Write a prime used twice as a power.
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