Pre-Algebra
Every lesson explains the concept, works through examples, and gives you practice problems with full solutions. Work through them in order, or jump to the topic you need.
12 lessons
- Variables and Expressions: Letters That Stand for NumbersWhat a variable is, how to write an algebraic expression from a sentence, why 3n means multiplication, and how an expression differs from an equation.
- Parts of an Expression: Terms, Coefficients and ConstantsHow to break an expression into terms, name the coefficient and constant, and describe a whole expression as a sum, product, quotient or difference.
- Evaluating Expressions: Substituting a ValueHow to evaluate an algebraic expression by substituting a value for the variable, why brackets matter when the value is negative, and how order of operations applies.
- Properties of Operations and Equivalent ExpressionsThe commutative, associative, distributive and identity properties, what each one permits, and how to check whether two expressions are equivalent.
- Combining Like TermsWhat makes two terms alike, how to collect them by adding their coefficients, why the variable part never changes, and how to move terms safely with their signs.
- The Distributive Property: Expanding and FactoringHow to multiply across a bracket, why the area model explains it, how a negative outside the bracket changes every sign, and how to factor by reversing the process.
- Writing Equations and Inequalities from WordsHow to turn a worded problem into an equation or inequality, what solving actually asks, which words signal each inequality sign, and how two quantities relate.
- How to Solve One-Step EquationsSolve one-step equations by doing the same inverse operation to both sides, with worked examples, common mistakes, and practice problems with full solutions.
- How to Solve One-Step InequalitiesSolve one-step inequalities the same way as equations, plus the one rule that changes: why the sign flips when you multiply or divide by a negative.
- How to Solve Two-Step EquationsSolve two-step equations by undoing addition first and multiplication second, with worked examples, common mistakes, and practice problems with full solutions.
- How to Solve Multi-Step EquationsSolve multi-step equations by distributing, combining like terms, then undoing operations in reverse order, with worked examples and practice problems.
- What Slope Is, and Why It Never Changes on a LineLearn what slope measures, how to find it with rise over run and the slope formula, and why similar triangles guarantee it is the same everywhere on a line.