May someone explain to me how to do this in the easiest way? i don't really understand. ❤

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! 

A= r2 × 3.14 11×11 ↓ ↓ 121 × 3.14 = 379.94 → 379.9