Just about every mathematical operation performed by built-in perl (mathematical) operators and functions is performed on binary-value operands.
in reply to built in function for binary division
You can FORMAT the input and output to look like decimal or binary numbers. Most humans prefer to look at the default formatting in decimal.
"By three methods we may learn wisdom: First, by reflection, which is noblest; Second, by imitation, which is easiest; and third by experience, which is the bitterest."