The Singing Hedgehog Guide to:

Prime Factors 4 - Mr H's Tree Method

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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

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

Previous Method Prime FactorsExample: 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 2^{3}x5x7]

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