The drill · ready · 60 seconds
Quick Math.
MathSixty seconds on the clock. As many problems as you can answer before it hits zero. No submit button — the next one drops the instant you're right.
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DifficultyMedium
Operations+ − × ÷
Round length60 seconds
Round over.New PB · +1
0
correct
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Appendix A · five techniques
§A.1 · Addition
01
Two-digit addition
Break each number into tens and ones, add separately, combine. Left-to-right avoids the carry step.
§A.2 · Subtraction
02
Count up. Don't borrow.
Subtraction is distance. From 47 jump +3 to 50, then +33 to 83. Add the hops.
§A.3 · Multiplication
03
Split and add
Split one factor into a clean tens piece plus a leftover. Every two-digit problem reduces to facts you know.
§A.4 · Division
04
Flip it into multiplication
"Eight times what is seventy-two?" Your times-table memory hands you nine. Every × fact doubles as a ÷ fact.
§A.5 · Benchmark
05
Forty good. Sixty competitive.
Medium · all ops · 60s. Under 15 almost always means a times-table gap — drill ×-only on Easy for three rounds.
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How to get faster at mental math.
Appendix B · referenceSpeed on a drill like this is 90% fact recall and 10% tricks. The good news is that both sides improve quickly with short, focused reps. Below are the patterns that actually move the needle — the same ones traders, cashiers, and waitstaff rely on when a phone isn't an option.
§B.1 · Addition
01
How do I get faster at adding two-digit numbers?
Break each number into its tens and ones, add them separately, then combine. The schoolbook "stack and carry" method is slower in your head because you have to remember the carried digit while you're still working. Doing it left-to-right avoids that entirely.
Walk through 47 + 38:
- Add the tens first: 40 + 30 = 70.
- Add the ones: 7 + 8 = 15.
- Combine the two results: 70 + 15 = 85.
That's it — three small additions, no carrying, done. Try 62 + 29: 60 + 20 = 80, then 2 + 9 = 11, then 80 + 11 = 91.
Example: 8 + 7. Pull 2 off the 7 and give it to the 8 — now you have 10 + 5, which is instantly 15.
Same trick at bigger numbers: 28 + 47. Pull 2 off the 47 to turn 28 into 30. Now it's 30 + 45 = 75. You traded a messy problem for an easy one.
§B.2 · Subtraction
02
What's the trick for subtracting in your head?
Don't subtract — count UP from the smaller number to the bigger one. The answer is how far apart they are, and walking up in two easy hops is faster (and way less error-prone) than the schoolbook borrow method.
Walk through 83 − 47:
- Start at 47. First hop: get to the nearest clean ten. 47 → 50 is a jump of +3.
- Now you're at 50. Second hop: get to 83. 50 → 83 is a jump of +33.
- Add the two hops together: 3 + 33 = 36. That's the distance between 47 and 83, which is the answer. So 83 − 47 = 36.
The whole point: you never subtract, you never borrow. You add two small numbers and you're done. Try 62 − 38: 38 → 40 (+2), 40 → 62 (+22), total 24. So 62 − 38 = 24.
§B.3 · Times tables
03
Do I still need to memorize times tables?
Yes, through 12×12. There is no trick that substitutes for this. If 8×7 takes more than half a second, drill that single fact before anything else — on the mul-only setting, Easy difficulty, for three rounds. It will click. Every multi-digit multiplication problem later reduces to a sequence of these single facts, so a slow table is a tax on everything above it.
§B.4 · Multiplication
04
How do I multiply two-digit numbers without a calculator?
Split one of the numbers into a clean tens-piece plus a leftover. Multiply each piece separately. Add. Multiplying by 10 is free (just shift a zero on), so always split off the tens part first — the leftover is a single-digit multiplication you already know by heart.
Walk through 14 × 6:
- Split 14 into 10 + 4.
- Multiply each piece by 6: 10 × 6 = 60, and 4 × 6 = 24.
- Add the two results: 60 + 24 = 84.
Walk through 12 × 15:
- Split 15 into 10 + 5.
- Multiply each piece by 12: 12 × 10 = 120, and 12 × 5 = 60.
- Add: 120 + 60 = 180.
9 × 7: do 7 × 10 = 70, then 70 − 7 = 63.
9 × 13: do 13 × 10 = 130, then 130 − 13 = 117.
Same logic for × 99 (multiply by 100, then subtract the original). And there's a pretty × 11 trick for two-digit numbers: write the first digit, then the sum of the two digits, then the last digit. So 11 × 34 → 3, then 3+4=7, then 4 → 374. (If the middle sum is 10 or more, carry the 1 like normal: 11 × 58 → 5, 5+8=13, 8 → 6, 3, 8 → 638.)
§B.5 · Division
05
How do I divide quickly in my head?
Flip division into a multiplication question. Instead of asking "how many times does 8 go into 72?", ask "8 times what is 72?" — and let your times-table memory hand you the answer.
Walk through 72 ÷ 8:
- Rephrase: 8 × ? = 72.
- Reach for your 8-times table. 8 × 9 = 72.
- So the ? is 9. That's the answer.
This is why the drill up top generates division as the inverse of multiplication. Every × fact you learn doubles as a ÷ fact: train 8 × 9 = 72 once, and you've also trained 72 ÷ 8 = 9 and 72 ÷ 9 = 8. Three facts for the price of one.
§B.6 · Why bother
06
I have a calculator in my pocket. Why bother?
Three reasons. First, checking yourself — a calculator will happily return the wrong answer when you fat-finger an input; mental math catches typos the way a second pair of eyes catches typos. Second, reading numbers in real life — a bill, a speedometer, a sale tag, an estimate from a contractor. Fluent people sanity-check these in the time it takes to unlock a phone. Third, the cost of friction — if adding two three-digit numbers feels hard, you'll skip the math entirely and trust whatever number is put in front of you. That's the expensive habit.
§B.7 · Speed
07
How fast should I be?
On medium with all four ops at 60 seconds, a common benchmark is 40+ for "good" and 60+ for competitive. Casual target: 25. If you're under 15, don't panic — that just means one or two times-table facts haven't locked in yet. Run mul-only for three rounds on Easy, watch which pair trips you, and drill that specifically.
§B.8 · Hands
08
I know the answer but my hands are slower than my head.
Very common. Two options. First, play with the keyboard, not the mouse — digits on the number row are much faster than hunting for the on-screen keypad. Second, if you still feel like your fingers are the bottleneck, try Untimed for a few rounds just to rebuild the reflex; speed returns once the look-and-type loop stops feeling deliberate.
Tools that help.
Appendix C · gearAs an Amazon Associate, we earn from qualifying purchases. We only link to things that are genuinely useful for the skill this page is about.
§C.1 · Tricks book
01
Mental math tricks book
Arthur Benjamin's "Secrets of Mental Math" is the standard. Cheap, practical, and the techniques actually stick.
§C.2 · Flash cards
02
Multiplication flash cards
Times-table gaps don't fix themselves. Ten minutes a day with physical cards beats any app at this.
§C.3 · Abacus
03
Abacus
The "make-a-ten" trick above is literally how abacus users think. A cheap one on your desk is a surprisingly good trainer.