Simplifying complex fractions: Where does the 3 in 21 and 15 come from? I understand how 14 and 21 became 2 & 3
(because both 14 & 21 are divisible by 7)
but I'm confused as to how the 1 came
about.

Simplifying complex fractions Where does the 3 in 21 and 15 come from I understand how 14 and 21 became 2 amp 3 because both 14 amp 21 are divisible by 7 but Im class=