Mental Math Practice

Press Start, type the answer to each sum on your keyboard or the number pad on the page, and get a score in correct answers per minute.

5 + 6 Press Start, then type or tap the answer. No Enter needed. The clock starts when you press Start.
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Sums up to 18. Learn the pairs that make ten, such as 3 + 7 and 4 + 6, and bridge through ten: 8 + 5 is 8 + 2 + 3 = 13.

–This run

–Your best

–Last run

1 min of questions. An answer is checked as soon as it has enough digits. The result is correct answers per minute; a wrong answer counts against accuracy.

No runs yet. Your last ten will show up here.

Drill of the day

One round is picked each day, the same for everyone. Finish it and a badge counts your days in a row.

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Next step Now hold a longer number in your head

How it works

This mental math practice is a typed-answer drill: a sum appears, you type the answer, and the next one arrives at once. Pick one of 33 drills, from single-digit sums to squares near 50, set a run of 30 seconds to 5 minutes, and answer on your keyboard or the number pad on the page. Each run ends with correct answers per minute, accuracy and the exact facts you missed.

Read the full guide

How a run works

Choose a drill in the Drill menu and a Run length of 30 seconds, 1, 2 or 5 minutes, then press Start. One question shows at a time. Type the answer and it is checked as soon as the last digit goes in, so there is no Enter to press. A right answer moves straight on. A wrong one shows the correct answer for a second and goes on your missed list. When the clock stops you see correct answers per minute, accuracy, your slowest question and every fact you missed.

33 drills, each with one strategy

Every drill practises one kind of sum and comes with one way to do it in your head. Multiply by 11 uses the digit-sum shortcut: 11 × 43 is 4, then 4 + 3, then 3, so 473. Change from 100 takes the tens digit from 9 and the ones digit from 10, so 100 − 37 is 63. Squares ending in 5 multiplies the tens digit by the next number up: 65 squared is 6 × 7 = 42 with 25 written after it, 4,225. The menu groups the drills under addition, subtraction, multiplication, squares, division, percentages and mixed.

Drill of the day, saved drills and bests

Drill of the day is chosen by the date, so everyone gets the same one on the same day. Finishing it on days in a row builds a streak. Press Save drill to keep a drill on your saved list. Each drill stores a personal best and a chart of your last ten runs for each run length. Copy result copies a link with the drill, the run length and your score, so a friend can take the same drill.

  • Say the running total, not the digits. For 48 + 37 think seventy, then eighty-five, and the answer is ready to type from the left.
  • Go for accuracy before pace. Every wrong answer shows its correction for a second, and that second comes out of your run.
  • When the same fact lands on your missed list twice, write it out once on paper, then run the drill again straight away.
  • Use the number pad if your keyboard has one, and keep your eyes on the question.
  • Keep the run length the same from day to day. A 1-minute rate and a 5-minute rate are different measurements.

Questions and answers

How is the score worked out?

The headline number is correct answers per minute: right answers divided by the length of the run in minutes. Accuracy is right answers as a percentage of everything you answered. Both are shown because they pull in different directions: 24 a minute at 100% and 27 a minute at 82% are different kinds of progress, and the second is a hint to slow down.

Can I use this as a daily mental math trainer?

Yes, that is what Drill of the day is for. The pick is set by the date, and the streak counter adds one for each day in a row you finish it. One routine that takes about three minutes with 1-minute runs: the daily drill, then one drill from your saved list, then Mixed facts warm-up.

Can a question or an answer be wrong?

It should not be possible, because no answers are stored. Each question is built in your browser from the number ranges of the drill, and the answer is computed at that moment by the same code that checks what you type. Division always comes out exactly and subtraction never drops below zero. If you do see a mistake, please report it through the contact page.

Which drill should I start with?

Start where you are nearly perfect, not where you struggle. If Times tables 2 to 9 is not at 100% accuracy, stay there, because every multiplication and division drill above it leans on those facts. Drills are marked starter, steady or stretch. For bills, tips and discounts, Add two digits with carrying, Fifteen percent and Percentages from 10% are the ones to keep.

Does it work on a phone, and is anything sent anywhere?

It works on a phone: the number pad on the page has large keys and stays in the same place for every question. Scores, streaks, saved drills and missed facts are stored in that browser only, so a phone and a computer keep separate records. There is no account. A link to your score exists only if you press Copy result, and the score is written into the link itself.

All 33 drills

Addition 6

  • Add a column of five digits Look for pairs that make ten before you start: in 7, 4, 3, 8, 6 take 7 + 3 and 4 + 6, then add the 8 for 28.
  • Add a number ending in 9 Round up, then step back one: 56 + 29 is 56 + 30 − 1 = 85. The same move works for numbers ending in 8, stepping back two.
  • Add single digits Sums up to 18. Learn the pairs that make ten, such as 3 + 7 and 4 + 6, and bridge through ten: 8 + 5 is 8 + 2 + 3 = 13.
  • Add three-digit numbers Hundreds, then tens, then ones, keeping one running total: 347 + 286 goes 500, then 620, then 633.
  • Add two digits with carrying Still left to right: 48 + 37 is 40 + 30 = 70, then 8 + 7 = 15, so 85. Hold the running total in your head, not the separate digits.
  • Add two digits without carrying Add the tens first, then the ones: 42 + 35 is 70 and 7, so 77. Working from the left means you say the answer in the order you work it out.
Show all 33 drills (27 more)

Subtraction 5

  • Change from 100 Take the tens digit from 9 and the ones digit from 10: for 100 − 37 think 9 − 3 = 6 and 10 − 7 = 3, so 63.
  • Change from 1,000 Take every digit from 9 and the last one from 10: 1,000 − 364 gives 6, 3 and 6, so 636.
  • Subtract a digit from a teen Go down through ten: 15 − 8 is 15 − 5 − 3 = 7. Split the number you are taking away so that the first part lands on ten.
  • Subtract a number ending in 9 Take off the round number above it and give one back: 74 − 39 is 74 − 40 + 1 = 35.
  • Subtract two-digit numbers Count up from the smaller number: for 83 − 47 go from 47 to 50, which is 3, then from 50 to 83, which is 33, so 36.

Multiplication 9

  • Double and halve Halve one number and double the other until the sum is easy: 16 × 35 becomes 8 × 70 = 560.
  • Multiply by 5 Halve the number and multiply by ten: 5 × 46 is 23 × 10 = 230. For an odd number, do the even number below it and add 5: 5 × 47 is 235.
  • Multiply by 9 Multiply by ten and take the number away once: 9 × 34 is 340 − 34 = 306.
  • Multiply by 11 Split the two digits and put their sum in the middle: 11 × 43 is 4, 7, 3, so 473. If the sum is ten or more, carry one to the left: 11 × 68 is 6, 14, 8, so 748.
  • Multiply by 25 Divide by four and multiply by 100: 25 × 36 is 9 × 100 = 900. Each one left over from the division is worth 25, so 25 × 37 is 925.
  • Multiply two numbers just under 100 Take each number from 100. Subtract both gaps from 100 for the first two digits, and multiply the gaps for the last two: 97 × 94 has gaps 3 and 6, so 91 and 18, which is 9,118.
  • Times tables 2 to 9 Swap the order when one way round is easier: 7 × 6 and 6 × 7 are the same fact, 42. The missed-facts list after the run shows which ones to repeat.
  • Times tables to 12 For 12 times a number, add ten of it and two of it: 12 × 7 is 70 + 14 = 84. For 11 times a single digit, write the digit twice.
  • Two digits times one digit Multiply the tens first and add the ones: 7 × 46 is 280 + 42 = 322.

Squares 3

  • Squares ending in 5 Multiply the tens digit by the next number up and write 25 after it: 65 squared is 6 × 7 = 42, so 4,225.
  • Squares near 50 Start from 2,500, add or take away 100 for each step from 50, then add the square of the gap: 53 squared is 2,500 + 300 + 9 = 2,809, and 47 squared is 2,500 − 300 + 9 = 2,209.
  • Squares to 20 Build on a square you already know: 13 squared is 12 squared plus 12 plus 13, which is 144 + 25 = 169.

Division 5

  • Divide by 4 Halve, then halve again: 348 ÷ 4 is 174, then 87.
  • Divide by 5 Double the number and divide by ten: 385 ÷ 5 is 770 ÷ 10 = 77.
  • Division facts to 81 Turn it round into a times-table question: 56 ÷ 7 asks which number times 7 makes 56, and the answer is 8.
  • Halve a three-digit number Halve each place from the left: half of 736 is 350 + 15 + 3 = 368.
  • Three digits divided by one digit Break the number into pieces the divisor fits: 294 ÷ 6 is 240 ÷ 6 plus 54 ÷ 6, so 40 + 9 = 49.

Percentages 3

  • Fifteen percent Add 10% and half of it: 15% of 60 is 6 + 3 = 9, and 15% of 240 is 24 + 12 = 36.
  • Percentages from 10% Find 10% by moving the decimal point one place, then scale it: 30% of 250 is 25 × 3 = 75, and 5% is half of 10%.
  • Quarter, half and three quarters Read 25% as a quarter and 75% as three quarters: 75% of 84 is 84 ÷ 4 = 21, times 3, so 63.

Mixed 2

  • Mixed facts warm-up Single-digit sums, teen subtractions, times tables to 9 and their division facts, shuffled together. Changing operation every question is harder than it sounds, so expect a lower rate than in a single drill.
  • Mixed two-digit workout Two-digit addition with carrying, two-digit subtraction, two digits times one digit and three digits divided by one digit, in random order. This is the round to use for a weekly check on the same settings.

How this list was compiled: Drills and strategy notes written for this page. Questions are generated in the browser from the number ranges stored with each drill, and every answer is computed at that moment, not looked up, so an answer key cannot be wrong. Ranges are set so that every answer is a whole number of zero or more. The worked example in each note was checked by calculation on 2026-09-18. The strategies are standard arithmetic identities, for example 25 × n = (n ÷ 4) × 100 and (n + 1) squared = n squared + n + (n + 1), not facts taken from another site. Licence: own work

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