Order of Operations (PEMDAS)
PEMDAS is the universal order that guarantees everyone gets the same answer from the same expression.
This is a free explanation of Order of Operations (PEMDAS) — a preview, not the full interactive lesson. The lesson, practice, quizzes, and AI Tutor are inside the app.
The order you tackle operations in can completely change your answer. Consider 3 + 4 × 2: working left to right gives 14, but multiplying first gives 11. Only one can be right, so math follows one agreed order.
PEMDAS gives that sequence: Parentheses first, then Exponents, then Multiplication and Division (left to right), then Addition and Subtraction (left to right). A common memory phrase is “Please Excuse My Dear Aunt Sally.”
Multiplication and Division share the same priority level, and so do Addition and Subtraction — don’t assume multiplication always comes before division; work left to right, doing whichever you hit first. Always scan the whole expression for higher-priority operations before you start.
Worked example
Evaluate: (5 + 3)² ÷ 4 − 1
- Parentheses first: 5 + 3 = 8, giving 8² ÷ 4 − 1.
- Exponent next: 8² = 64, giving 64 ÷ 4 − 1.
- Multiplication and division, left to right: 64 ÷ 4 = 16, giving 16 − 1.
- Addition and subtraction, left to right: 16 − 1 = 15.
15
This concept also comes up in Constants, Variables, Terms & Expressions, Powers, Roots & Absolute Value.
Inside the app, Order of Operations (PEMDAS) comes with:
Read the explanation here for free — then practice it for real, with everything you need in one place.
- Practice sets — Open-book practice questions at your level, easiest-first — as many as you want, never scored.
- Quizzes — Scored quizzes on the whole lesson, so you know when you’re ready to move on.
- Skills Check — A concept-by-concept map of what you’ve mastered and what to focus on next.
- Worked examples — Tap the Brain Button on any example for alternative step-by-step explanations.
- Glossary — Plain-English definitions of every key term in the lesson.
- Formula sheet — The GED® & HiSET® formula sheets, on screen while you practice.
- Practice calculator — An on-screen calculator to build your calculator skills before test day.
- Math-fact flashcards — Quick drills for addition, multiplication, perfect squares, and square roots.
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