You can
put this solution on YOUR website!
Make a factor tree:
100 <- The smallest prime that goes into 100 is 2, and 100 = 2×50
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2 50 <- The smallest prime that goes into 50 is 2, and 50 = 2×25
/\
2 25 <- The smallest prime that goes into 25 is 5, and 25 = 5×5
/\
5 5 <- 5 is prime so you're done.
100 = 2×2×5×5 = 2²×5²
Edwin