To solve this expression, we need to follow the order of operations, which is parentheses, exponents, multiplication and division (from left to right), and addition and subtraction (from left to right).

1/5 * 4/7 = 4/35
3/7 * 1/5 = 3/35

Now we can substitute these values back into the expression:

4/35 + 3/35 - 1/5

To add or subtract fractions, we need a common denominator. In this case, the common denominator is 35.

(4 + 3 - 7)/35

Simplifying the numerator:

= 0/35

The final answer is 0/35, which can be simplified to 0.