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A shopkeeper counts bangles by the dozen, not one by one. A dozen is 12. Numbers can be written in many ways.

This is Part I, Chapter 3: A Story of Numbers.

What you will learn

• One mark each — the plainest count, and why it reads slowly.
• Bundles — a gap every few marks turns marks into bundles.
• Symbols added — some systems total the symbols written.
• Where it sits — each column gives a symbol its own worth.
• A mark for nothing — without it, two numbers look the same.
• Ten symbols — position and a zero write every number.
• Two ways of adding — one sum, two different costs.
• Writing it down today — one amount, several ways to write it.

Every lesson has a lab. Move the numbers and watch the count change.