First, we go from small numbers. we know that both 68 and 80 are divisible by 2 which means that we can simplify the numbers dividing by 2. So it is 34/40. We know that again 2 is divisible by 34 and 40. So you divide 2 which gives 17/20. Now, no number is divisible by 17 and 20 so your answer is 17/20
