To subtract fractions, the denominators (bottom numbers) must be equal; so first convert the fractions into equivalent fractions with the same denominator. Then the numerators (top numbers) are subtracted and the resulting fraction simplified:
7/13 - 1/18 = 126/234 - 13/234
= 113/234
13/20 minus 3/5 is 1/20
1 over 18 I think
1 minus 11/24 is 13/24
It is: 13/39 - 4/13 = 1/39
6 over 13
16/18 - 9/18 = 7/18
13 - 1/5 = 12 4/5
5 over 18
17/18
13 over 45
2/3 is.
It is: 13/39 - 4/13 = 1/39