a/5-1/5=-6

ok, let's make 6 equal to a number over 5.

x/5=6. Since 5/5 is equal to one, to get 6 ones over 5, we multiply the numerator of 5 by 6. 5x6=30

so 6 equals 30/5.

now let us ADD 1/5 to both sides to make:
a/5=31/5
multiply by 5 to cancel out the denominators.
we get a=31

so 31/5 - 1/5 = 6 (30/5)