Convert the fractions so they both have the same denominator (bottom part of the fraction)
1/5 = 7/35
This is because 5*7=35, so 1*7=7
1/7 = 5/35
This is because 7*5=35, so 1*5 =5
Then subtract the top numbers to get the answer:
1/5 = 7/35
This is because 5*7=35, so 1*7=7
1/7 = 5/35
This is because 7*5=35, so 1*5 =5
Then subtract the top numbers to get the answer: