Pls me i know it's easy but i can't do it!

First, you need to make the numbers have a common denominator, and make them into mixed numbers.
1. 3 1/4 - 1 1/2
3 1/4 - 1 2/4
13/4 - 6/4 = 7/4 = 1 3/4

2. 5 2/9 + 4 11/13
5 18/117 + 4 99/117
603/117 + 567/117 = 1,170/117 = 10

3. 2 3/8 + 5 3/5
2 15/40 + 5 24/40
95/40 + 224/40 = 319/40 = 7 39/40
or this way...
2 + 5 = 7
15/40 + 24/40 = 39/40
7 39/40

4. 9 3/7 - 6 2/5
9 15/35 - 6 14/35
9-6= 3
15/35 - 14/35 = 1/35
3 1/35

5. 8 5/6 - 2 1/2
8 5/6 - 2 3/6
8 - 2 = 6
5/6 - 3/6 = 2/6 = 1/3
6 1/3

6. 7 3/4 + 5 1/8
7 6/8 + 5 1/8
7 + 5 = 12
6/8 + 1/8 = 7/8
12 7/8

7. 11 5/12 + 7/8
11 40/96 + 84/96
1,096/96 + 84/96 = 1,180/96 = 12 28/96 = 12 14/48 = 12 7/24

8. 13 4/5 - 8 1/6
13 24/30 - 8 5/30
13 - 8 = 5
24/30 - 5/30 = 19/30
5 19/30