Numbers have an order or arrangement.
The number two is between one and three.
Three or more numbers can be placed in order.
A number may come before the other numbers or it may come between them or after them.

Example: If we start with the numbers 4 and 8, the number 5 would come between them, the number 9 would come after them and the number 2 would come before both of them.

The order may be ascending (getting larger in value) or descending (becoming smaller in value).