The online book
Read the six adapted learning chapters in order, or choose a topic. Each chapter invites you to predict, explore, explain and check.
Chapter 1 · What is a number?
Read the chapter and its questions.
Chapter 2 · The basis of a number system
Read the chapter and its questions.
Chapter 3 · Decimal numbering system
Read the chapter and its questions.
Chapter 4 · Place value and operations
Read the chapter and its questions.
Chapter 5 · Meet the frame
Read the chapter and its questions.
Chapter 6 · Explore and reflect
Read the chapter and its questions.
Source and reading guide
This is the website adaptation, not a page-for-page reproduction of the original manuscript. The integrated review edition includes the original diagrams and mathematical limitations.
Download the master bookMathematical glossary and notation
Extend your learning
Workbooks
Printable questions and separate answer guides.
Self-check quiz
Explain your answer and learn from feedback.
Squares and roots
Explore multiplication, area and inverse operations.
Short demonstration
Watch nine units become one ten: play or step through the regrouping.