Ok, so 1 is a whole number. 1/5 is a fraction of 1. So you want to subtract 1/5 from 1. The number 1 is equal to 5/5. So if you subtract 1/5 from 5/5 you are left with 4/5. You do the same with the second one, just subtract 3/5 from 5/5 to get your answer.
What you want to do is convert the 1, a whole number into a fraction. Since the denominator is 5, 5/5 makes 1 whole. So your question now reads, 5/5 - 1/5. Change any equation so that you have all common denominators The second problem the whole number is still 5/5. So the equation becomes 5/5 - 3/5. With common denominators, it becomes a simple subtraction, 5 - 1 and 5 - 3 Hope it helped!