How it works
You start with 60 seconds on the clock and one arithmetic problem on screen. Type the answer and press Enter. The next problem appears right away, so there is no pause between questions.
Your goal is to solve 25 problems before the clock empties. Each correct answer adds 1.2 seconds back to the clock, so a good run stretches further than a minute. Each wrong answer takes 4 seconds away and shows you the number you missed.
Difficulty that follows your streak
The game tracks how many problems you have solved in a row. Every four answers in a row moves you up one level, to a maximum of level 5. The level decides both the size of the numbers and the operations you see.
Level 1 gives you addition and subtraction with small numbers. Multiplication joins at level 2, and division joins at level 3. Levels 4 and 5 keep all four operations but widen the number ranges. One wrong answer resets your streak to zero and drops you back to level 1, which makes a long clean run worth more than a scattered one.
Scoring and streaks
Each correct answer is worth 10 points per current level, plus 2 points for every answer in your active streak. So the tenth answer of a streak pays far more than the first. Subtraction never produces a negative result, and division is always exact, so every answer is a whole number you can type without a decimal point.
If you want a high score, protect the streak. Slowing down for half a second on a hard problem costs you less than a wrong guess, which takes 4 seconds and your whole streak multiplier with it.
Controls
Type digits on your keyboard and press Enter to submit. On a touch screen or with a mouse, use the on-screen keypad, then press Enter. Back deletes the last digit, and Quit ends the run early.
Frequently asked questions
Can the answer ever be negative? No. Subtraction problems always put the larger number first, so every answer is zero or above. You only ever need the digits 0 through 9.
What happens when I run out of time? The run ends and you see your score, how many problems you solved, and your longest streak. Your best score stays on screen for the next round.
Is there a penalty for guessing? Yes. A wrong answer costs 4 seconds, resets your streak, and sends you back to level 1 problems. Reading the problem twice is usually cheaper than guessing.