13/18 + 7/12Common denominator: 36(132 + 73) / 36(26 + 21) / 3647 / 36
5/7 - 3/5Common denominator: 35(55 - 37) / 35(25 - 21) / 354 / 35
5/6 - 3/8 - 1/2Common denominator: 24(54 - 33 - 1*12) / 24(20 - 9 - 12) / 24-1 / 24
Therefore, the solutions are:
13/18 + 7/12
Common denominator: 36
(132 + 73) / 36
(26 + 21) / 36
47 / 36
5/7 - 3/5
Common denominator: 35
(55 - 37) / 35
(25 - 21) / 35
4 / 35
5/6 - 3/8 - 1/2
Common denominator: 24
(54 - 33 - 1*12) / 24
(20 - 9 - 12) / 24
-1 / 24
Therefore, the solutions are:
47/364/35-1/24