Is zero a number?

Yes. 0 (zero) is both a number and the numerical digit used to represent that number in numerals. The idea to use zero as a number was probably not recognized until the early centuries C.E., when the Hindus and Arabs tried to solve mathematical equations and organized a systematic study of the properties of operations on numbers. In about 850 C.E. Mahavir, a Hindu mathematician, wrote in his book The Compendium of Calculation: “A number multiplied by zero is zero, and that number remains unchanged which is divided by, added to, or diminished by zero.” Today’s mathematicians agree with most of what this ancient thinker wrote. We can add or subtract zero to a number and get back that number. When we multiply a number by zero the answer is zero. However, division by zero is undefined.