What if the denominator were 9 and 7. How would you do it?
Ex: 5/9 + 6/7 =
You find the smallest number that both 9 and 7 goes into evenly.
Multiples of 9 = 9, 18, 27, 36, 45, 54, 63 . . .
Since 63 is the smallest number divisible by both 7 and 9, it's the common denominator.
63/9 = 7
Multiply both numerator and denominator by 7
5/9 = 35/63
63/7 = 9
6/7 = 54/63
35/63 + 54/63 = 89/63 = 1 26/63
6/7 =