Yes, zero is a number but you are not alone if you wonder why. Indian mathematicians first came up with the number idea around 650 AD. Originally, perhaps as early as 200 AD, they used zero as a placeholder in another number. For example, in our notation: 216 is a different number than 2016. This use of zero advanced trade, commerce, and bookkeeping but does not qualify zero as a number. Zero, in its place-keeping function, is a kind of punctuation mark to help us interpret numbers correctly.