The quiz shows 12 expressions, one at a time. Each expression mixes two or more operations, and some have brackets or a power. Work out the value in the correct order.
You get one answer for each expression. A wrong answer shows the correct value, then the quiz moves on. The end screen lists every expression again, and when your answer matched a common mistake it names the step that went wrong: "You added before you multiplied."
How to play
The clock starts at your first keystroke and counts up. There is no time limit.
Expressions come one at a time, in order. You cannot skip one.
Type the value, then press Enter. The answer commits only on Enter.
You get one answer per expression. A wrong answer shows the correct value, then the quiz moves on. The end screen names the step that went wrong, when the quiz can tell.
The order is: brackets, then powers, then multiplication and division, then addition and subtraction. Operations on the same level go from left to right.
Your score is the number of expressions you got right, out of 12. A tie ranks by time.
Give up ends the run early and shows your results.
Select "Review answers" on the result screen to see each expression you played, and the step that went wrong.
What counts in this quiz
12 expressions per run, freshly generated each run, in 4 levels of 3. Every value is a positive whole number.
Level 1: two operations without brackets, such as 2 + 3 × 4. Level 2: three operations, and the first brackets, such as (5 + 3) × 4. Level 3: chains on one level, such as 20 − 5 − 3, squares, and a bracket with division. Level 4: nested shapes, such as 3 × (2 + 4)² and (9 − 5)² ÷ 4.
The quiz recognises five mistakes: adding before multiplying; working left to right; skipping the brackets; multiplying before applying the power; and reading a chain from right to left.
What's not included, and why
No negative values, no fractions, no remainders. Every division divides out.
No expression is ambiguous. The quiz never uses the a ÷ b(c) shape that people argue about online.
Good to know
PEMDAS is the American mnemonic. The UK teaches BODMAS and India BODMAS or BIDMAS. The rules are the same; only the letters differ.
The viral "8 ÷ 2(2 + 2)" puzzle has two answers because it is badly written, not because the rules are unclear. Two conventions for implied multiplication disagree.