Subtraction equations represent an unknown quantity in a relationship such as or , with values drawn from whole numbers, decimals, fractions, or signed numbers appropriate to the context. Solving preserves equality by using addition or subtraction to undo the operation, interpreting subtraction’s order correctly, and checking the solution by substitution; this scope is limited to one-step linear equations, not multi-step equations or variables on both sides.
A subtraction equation has an unknown number, often represented by . To solve it, undo the subtraction by adding the same number to both sides. This keeps the equation balanced.
Example:
Step 1: Identify what is being subtracted.
The number is subtracted from .
Step 2: Add to both sides to undo the subtraction:
Step 3: Simplify.
On the left, , so only remains:
Step 4: Check the solution.
Substitute for in the original equation:
This is true, so the solution is
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