Here’s a quick one: All rational numbers except 0 can be expressed as (−1)sΠpnii where s∈{0,1}, pi is a prime number, and ni is an integer.
This reminds me of the restriction on the definition of rationals, i.e., that ab is a rational number for all integers a and b except b=0. However, this can be written to make zero less exceptional: All rational numbers can be written in the form ab where a∈Z and b∈N∗.