Algebra on a Grid

An equation can be drawn, and once it is, every answer it has is visible at the same time. This series starts with how a pair of numbers names a place, then reads values off a line, then shows where the line comes from — and finishes with the thing that makes it straight in the first place.

48 min to complete

Beginner level

4 Parts

CodePLU Goal

Upgrading Human Mental Models

Learn how to think in Workflows

Along the corridor, then up the stairs — and never the other way

Beginner 12 min Part 1

What Are Coordinates and How Do You Plot a Point?

A pair of coordinates is an address on a grid, and the order is the whole of it. Learn how to read and plot a point in an interactive playground.

Go up from the axis until you meet the line, then across

Beginner 12 min Part 2

How Do You Read a Value Off a Graph?

A graph answers questions you never calculated, if you can read it. Learn how to go from an x value to its y value, and find three of them in a playground.

Every point on the line is a pair that makes the equation true

Beginner 12 min Part 3

What Does the Graph of an Equation Look Like?

A graph is not a picture of an equation — it is every solution of it, plotted at once. Learn what the line means and match three equations in a playground.

The same step, every single time you move across

Beginner 12 min Part 4

What Makes a Graph a Straight Line?

A graph is straight when the rise per step never changes. Learn what steepness means, what a downward line says, and match three steps in a playground.