Lesson 3: Solving Equations Using Addition or Subtraction

Property

To solve equations, we apply the rules of equivalence to isolate the variable.
For equations in the form $x + p = q$, we find the solution by subtracting $p$ from both sides.
For equations in the form $x - p = q$, we find the solution by adding $p$ to both sides.
All numbers $p$, $q$, and $x$ are integers or rational numbers.

Examples

Property

Use variables to represent unknown quantities in word problems and construct simple equations that can be solved using addition or subtraction. This involves identifying the unknown, assigning it a variable, and translating the problem into an equation of the form $x + a = b$ or $x - a = b$.

Examples