With the invention of the zero, we would still need some way to tell the value of each figure when writing a number. The invention of the zero made it possible to drop the words or marks used to show place value or values, and to use the position of a figure in a number to show its value.

Any time we deal with the shape, size, and position of objects in space, we are involved in geometry. When prehistoric people did a certain kind of weaving and decoration, they were using geometry without knowing it.