Twenty tiny equations, one at a time, each with a single unknown: "x + 7 = 15" — type 8 and the next one appears. Every equation is one-step: an addition, a subtraction (on either side), one multiplication like 4x = 36, or one division like x ÷ 6 = 7.
It's algebra with the training wheels of arithmetic: if you can undo one operation, you can clear the board. You get one minute for all 20, which is enough time once the solving feels automatic rather than deliberate.
How to play
You have one minute. The clock starts at your first keystroke, not when the page opens.
One equation at a time, solved in order — enter the value of x, not the whole expression.
An exact answer auto-commits as you type; Enter is optional and a wrong guess just shakes the box, penalty-free.
The run ends when the minute is up, or sooner if you solve all 20.
Your score is the number you solved. A tie is broken by the faster time.
Give up any time to end the run and see how far you got.
What counts in this quiz
20 one-step equations per sprint, freshly generated each run.
Five shapes appear: x + a = c, x − a = c, a − x = c, ax = c, and x ÷ a = b — never more than one operation to undo.
x is always a positive whole number; in the division shape it can reach 108 (up to 9 × 12), everywhere else it stays below 30.
What's not included — and why
No two-step equations — anything like 3x + 5 = 26 is out of scope, so every problem stays a pure one-move puzzle.
No negative or fractional solutions — every x is a positive integer by construction.
Good to know
"Algebra" comes from al-jabr — "the reunion of broken parts" — from the title of a 9th-century book by the Persian mathematician al-Khwarizmi.
Using the letter x for the unknown is usually credited to René Descartes' 1637 La Géométrie.