Arithmetica — Play Free Online

Arithmetica (written ArithmeticA on its title screen) is a mental maths game by Eidosk, the developer of the Fast Typer series. It looks like a chalkboard: a sum appears with a gap in it, a row of possible answers sits underneath, and you pick the right one before the time bar empties. Quick correct answers push the timer back up, so the game lasts as long as you keep answering fast and accurately.

How to play

Click the number that completes the equation. On a phone or tablet you tap it instead; the game is laid out in portrait, so it fits a phone held upright. Only quick correct answers add time, and when the bar reaches zero the run ends and you get your final score and a grade.

Levels

A run climbs through levels, and each level changes what kind of sums you get and how many answers you choose from. The early ones go roughly like this:

1. Simple additions with only 2 choices.
2. Simple subtractions with 3 choices.
3. Additions and subtractions mixed.
4. Simple multiplications.
5. All three of those mixed together.
6. Simple divisions.
7. All four operations with 4 choices.
8. Choose the sign: the numbers are given and you pick the missing operator.

After that come long operations with several steps, square roots, percentages, squares, and sums with parentheses. The last stage is Level Infinity, which never ends.

Grades, achievements and rewards

Each run is graded from F up to A+ depending on how many questions you answered correctly. The achievements follow the same path: Bright, Awesome and Amazing! for reaching a B, an A and an A+; The Sign, The Root and The Percent for solving your first operator, square root and percentage question; Accuracy for a long streak of correct answers; Flash! for fast answers plus Time Bonuses; and Infinity for reaching the never-ending level.

Achievements unlock rewards. Time Bonus pickups refill the time bar during a run, Level Select lets you start from any level up to the highest you have reached, and finishing every achievement opens Very Hard mode. A statistics screen keeps your games played, best accuracy and average reaction time.

Tips

• On the early levels speed matters more than anything, because quick answers bank extra time for the harder sums later.
• Keep an eye on how many answer buttons there are; the number of choices grows on later levels, so there is more to read before you click.
• Unlock Level Select early so you can practise square roots and percentages directly.