Solving Single-Variable Subtraction Equations

Solving Single-Variable Subtraction Equations

Introduction

A subtraction equation can represent a situation in which an amount is taken away from an unknown starting value. Solving the equation means finding the value of the variable that makes both sides ...

Daniel has a marble collection. He gives 15 marbles to his cousin and is left with 27 marbles.

To find how many marbles he started with, Daniel writes an equation, a math sentence showing that two expressions are equal. He uses a variable, the letter x, to represent the unknown starting number.

Giving away 15 marbles means s...