The Universal Calculation Engine
The Universal Calculation Engine

Leftover change from a simple purchase

Part of: Word Problems

A typical word problems problem: read what is asked before you calculate.

What to do first

For word problems, list knowns and unknowns. Check whether the problem wants a number, a relationship, or a graph. Word Problems is the reference lesson.

Read the question

Wrong answers on word problems often come from answering a different question than the one asked, especially “how many” versus “how much is left.”

Total and parts

You know a total and one part; you need the other part. Subtract the known part from the total, or write total = part₁ + part₂ and fill in what you know.

Sense-check

Core lesson

Related: Word Problems. Use the calculator with your own numbers when the example is not close to your case.

Use the calculator

FAQ

Where is the main lesson?

Word Problems has the full topic, examples, and practice links.

Which calculator first?

After your setup is on paper, open Percentage for a quick numeric pass.