➗ Mental Math: how to play and calculate faster
By Miguel Arechaga
Mental Math is a race-against-the-clock challenge to train your speed with numbers. Solving as many operations as possible in 60 seconds is addictive, and with a few quick-calculation tricks, your score will climb fast. Here they are.
What does it involve?
For 60 seconds, operations appear (addition, subtraction, multiplication, and, on hard mode, division) and you type the result. Every correct answer counts and moves you to the next one. The goal is to rack up as many correct answers as possible.
How to play
- Choose a level (Easy, Medium or Hard) and hit Start.
- An operation appears: type the result into the box.
- If you're right, it automatically jumps to the next one; press ENTER to submit your answer.
- You have 60 seconds. Your best score is saved in your browser.
Quick-calculation tricks
The first trick is breaking numbers apart. To add 47 + 38, add the tens first (40 + 30 = 70) and then the units (7 + 8 = 15), then combine: 85. For subtraction, do the same thing in parts. It's much faster and more reliable than calculating "the old-fashioned way".
The second is rounding and adjusting. To multiply 19 × 6, calculate 20 × 6 = 120 and subtract a 6: 114. For 98 + 45, add 100 + 45 = 145 and subtract 2: 143. And to multiply by 5, multiply by 10 and divide by 2 (24 × 5 = 240 / 2 = 120). These shortcuts save precious seconds.
Quick tips
- Don't get stuck on a hard operation: if you're unsure, keep going mentally with an approximation.
- Know your multiplication tables well; they're the foundation of speed.
- Start on Easy to build rhythm and move up a level once you've mastered the tricks.
Mental Math keeps your brain sharp and is a perfect complement to Sudoku. With decomposition and rounding, you'll solve many more operations per round.
🏆 Score ranking
Mental Math has its own global ranking: your best number of correct answers is saved. Go to Ranking, the 🕹️ 1 Player tab, choose "Mental Math" from the dropdown, and compare your score with other players, synced to your account. For your result to count you need a free account on MundoSudoku (just a username and password, no email required): you can play without one, but without logging in your score won't be saved to the ranking.
