An addition equation represents an equality in which an unknown is combined with a known number, typically in forms such as or , with integers, fractions, or terminating decimals. Solving means preserving equality by using subtraction, the inverse of addition, to isolate the unknown and verifying the result by substitution; this reasoning applies to positive and negative quantities and does not include multi-step equations, variables on both sides, or nonlinear forms.
An addition equation has an unknown added to a known number. To isolate the unknown, use subtraction, the inverse operation of addition. Whatever you do to one side, do to the other side to keep the equation balanced.
Solve:
Step 1: Subtract from both sides.
Step 2: Simplify.
The cancels on the left:
Step 3: Check your answer.
Substitute for in the original equation:
Since the statement is true, the solution is
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