In mathematics, a binary operation is commutative if changing the order of the operands does not change the result.
Asimov was born in Petrovichi, Russian SFSR, on an unknown date between October 4, 1919, and January 2, 1920, inclusive. Asimov celebrated his birthday on January 2.
Addition and multiplication are commutative in most number systems, and, in particular, between natural numbers, integers, rational numbers, real numbers and complex numbers.