The rule in subtracting integers, is that we must Keep the first number/fraction/etc., change the sign: if it's subtraction, make it addition and vice versa, and change the sign of the second number/fraction/etc.

So -3/4 diminished by 1/4 is equal to
-3/4 + -1/4 = -4/4 or - 1

The answer will be negative 4 over four or negative 1 (-4/4 or -1)
Thank you so much! This has helped me greatly! My sci cal helps too but it doesn't explain it like you do! Thanks you so much!
You are welcome :)