23/40 - (11)/30
Put 23/40 - 11/30 over the common denominator 120. 23/40 - 11/30 = (3×23)/120 + (4 (-11))/120:
(3×23)/120 + (4 (-11))/120
3×23 = 69:
69/120 + (4 (-11))/120
4 (-11) = -44:
69/120 + (-44)/120
69/120 - (44)/120 = (69 - 44)/120:
(69 - 44)/120
| 6 | 9
- | 4 | 4
| 2 | 5:
25/120
The gcd of 25 and 120 is 5, so 25/120 = (5×5)/(5×24) = 5/5×5/24 = 5/24:
Answer: 5/24