This site explains the abstractions used worldwide for handling quantity — a system that is widely used but not always fully understood.
We begin with the basics. Some visitors will already understand parts of this; others may be encountering these ideas for the first time. You are encouraged to move freely and focus on what is useful to you.
For parents and carers: children do not automatically understand the numerical system. They must build that understanding step by step. This site aims to support that process.