Divide the numbers. Subtract the Exponents. Adjust if necessary. This sounds very familiar.
You'll have to show intermediate results if I am to be able to tell you how to fix your error.
Did you forget how to "adjust if necessary" again?
Divide the numbers. 3/4 = 0.75 Subtract the exponents 20 - 5 = 15 Reassemble 0.75 E15 Adjust if necessary 7.5 E14 Watch yourself do it. It shouldn't be a mystery by the time you get to the end.