The Singing Hedgehog Guide to:
Prime Factors 4 - Mr H's Tree Method
For the 'cheaty' tree method we again write factor pairs but we start with a pair of numbers close together, probably not prime. This method gets to smaller numbers much quicker but the primes are not set out so nicely.

    Example:    Find the product of the prime factors of 280

 280 = 10 x 28; could have done 20 x 14

 could do 28 as 2 x 14 but 4 x 7 is quicker

 4 is only non-prime so we split it

 Both prime so we are finished

So the answer is 2x2x2x5x7 [or 23x5x7] 

Now you need to practise:

downloadable worksheet
(save this file then run it)

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