The first step is to convert each mixed number to improper fraction.
- 1 3/5 becomes - 8/5
- 2 5/8 becomes 21/8
The new expression is
- 8/5 - - 21/8
- 8/5 + 21/8
The LCM of the denominator is 40. Multiplying each term by 1/40, we have
(- 8 x 8 + 21 x 5)/40 = (- 64 + 105)/40
= 41/40
The final answer is 41/40
