Simple Arithmetic

Arithmetic, try as you might to sate her
with decimals and fractions of the whole,
demands more than a common numerator
when adding, as a point of protocol,
uneven parts. And ditto with subtraction.
Multiplication, that it does with ease,
both top and bottom get in on the action,
achieving simultaneous release.
(I might add, parenthetically, division,
the long one, and the short of it, in kind,
when otherwise unwrecked by indecision
won't pay an operator any mind)
So calculating, you might call it scheming,
though I believe that quality redeeming.