10/12 + 3/8 + what = 1 Find a common denominator. The smallest number that 12 and 8 will both go into is 24. Rewire the fractions with 24 as the denominator.
10/12 = 10/24 Multiple the top and bottom by 2
3/8 = 9/24 Multiple the top and bottom by 3
Now we have
10/24 + 9/24 + X/24 = 24/24 (24/24 is the equivalent to 1)
