How to calculate the mixed operation of addition and subtraction of rational numbers? Example: 2 1 — + (— —)— 1 + — 3 5 3

How to calculate the mixed operation of addition and subtraction of rational numbers? Example: 2 1 — + (— —)— 1 + — 3 5 3

Original formula = 2 / 3 - 1 / 5 - 1 + 1 / 3
=2/3 +1/3 -1 -1/5
=1-1-1/5
=-1/5