Arithmetic

Try it Yourself 5 Tracks 25 Concepts 4 hr 3 min of learning

CodePLU Goal

Upgrading Human Mental Models

Learn how to think in Workflows

Numbers Preview

Every number belongs to a family

Sorting a number into the right family is the first real maths skill — and it is much clearer when you can see the families side by side.

Drag nodes and connect the flow to understand the concept
Press enter or space to select a node. You can then use the arrow keys to move the node around. Press delete to remove it and escape to cancel.
Press enter or space to select an edge. You can then press delete to remove it or escape to cancel.

Tracks In This Category

Standalone Concepts

Self-contained concepts in this category. Each one stands on its own — start wherever you like.

Multiply straight across — and to divide, flip and multiply
Beginner 9 min

How Do You Multiply and Divide Fractions?

Multiply fractions straight across; to divide, flip the second and multiply. Work out four problems and land each on its value in an interactive playground.

Percent means 'out of 100' — so 25% is just 25 squares of a hundred
Beginner 8 min

What Does Percent Really Mean?

Percent means 'per hundred', so a percentage is how many out of 100. Match percentages to 100-square grids in an interactive playground.