Once upon a time, zero wasn’t really a number. Its journey to the fully fledged number we know and love today was a meandering one. Today, zero is both a placeholder, and tool, within our number system signifying an absence of a value, and as a number in its own right.
But it wasn’t always seen as that, and it still doesn’t act quite like other numbers. Can you divide by zero, for example? Hannah Fry explains how zero came about, from its origins in ancient civilisations, through the resistance it faced from the Roman numeral system, to being the cornerstone of calculus.