Subtracting Fractions

Question 1:

6 8 - 1 8
5 8

Question 2:

4 9 - 2 9
2 9

Question 3:

7 10 - 3 10
4 10 = 2 5

Question 4:

7 8 - 10 20
15 40 = 3 8

Question 5:

7 8 - 3 10
23 40

Question 6:

8 20 - 1 4
3 20