To simplify the fraction -3/16 - 1/20, we need to find a common denominator. The common denominator for 16 and 20 is 80.
Converting -3/16 to have a denominator of 80, we get -15/80.
Converting -1/20 to have a denominator of 80, we get -4/80.
Now, we can combine the fractions: -15/80 - 4/80 = -19/80.
So, the simplest form of -3/16 - 1/20 is -19/80.