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MIDDLE SCHOOL

Mathematics (Grade 7)

Expressions and Equations

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Expressions and Equations: Multi-Step Problems and Reasonableness

Working Backwards

Description

Working Backwards

Introduction

Working backward is useful when the final result is known, but the starting value is unknown. Each operation is undone in reverse order to recover the original value.

Theory

Transcript

Diego finishes the hardest level in his favorite video game, and the screen shows a final total of 40 gold coins.

The challenge is to find out how many coins he had before the level began.

During the level, a treasure chest doubled his coins, and a spike trap then took away 10 coins.

The situation is represented by the equation...

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