Quick Math

The question, and how you win

A question is a single line of digits and signs — 7 + 8 = ? — with a keypad under it. You type the answer, and a counter in the top bar says where you are in the set: 3 / 10.

A level is 10 questions, and it is cleared once all 10 have been answered correctly. Questions cannot be skipped — you stay on one until it is right — and there is no game over. Every set you start can be finished.

The questions carry no words at all. They are built from digits and the six signs + − × ÷ = ?, which mean the same thing in all 14 languages the app ships in, so a question reads identically whatever your language is set to. The progress counter is on screen because how much is left is a fact; it is not there to hurry you.

Typing an answer

The keypad is 0–9 plus one key that deletes the last digit. There is no minus sign and no decimal point, and that is not a limitation the game works around: every answer is a whole number of 0 or more, because no question is built that could need anything else.

• There is no OK button. Your answer is judged the moment you have typed as many digits as the answer has — one tap per digit, and no more.
• The blank is sized to the answer before you type, so it shows how many digits it is waiting for. Judging by digit count cannot hide that, so the game shows it plainly rather than pretending otherwise.
• The delete key steps back through what you have typed, but only up to the point of judgement. It corrects a mistype; it is not an Undo.
• An answer never runs past 3 digits, which caps both how much typing one question can ask for and how long the game waits before it judges.
• Your digits appear in the blank itself, marked by an outline and by the figures rather than by colour alone.

Judging by digit count is what keeps the tempo, and tempo is most of what a drill is for: an OK button would make a 1-digit answer 2 taps and add 10 taps to a level. The cost is real and worth saying plainly — a 1-digit answer is judged the instant you mistype it, with no room to take it back. That is only affordable because a wrong answer carries no penalty and the same question comes straight back.

Wrong answers, and the help you get

A wrong answer clears what you typed and puts the same question back on screen. The game counts it, and counting it is the whole of what happens.

There is no penalty of any kind. No time is taken away, no questions are added, and a level cannot be failed. The game does not scold you either — no warning tone, no vibration, no red flash. Your input disappears and you can type again.

• There is no Hint. Doing the arithmetic is what this game is made of, so a hint would carry the content away with it. Showing the working was considered, but in a question with one step in it the working is the answer.
• There is no Undo. A judged answer was either right or wrong, so there is nothing to take back — and a wrong one already costs nothing and hands the question straight back to you.
• Re-solving is unlimited and free. A retry button on the game screen starts the set again from the first question, and any unlocked level can be picked again as often as you like — it is always the same 10 questions.
• A set in progress is saved, so you can put it down mid-level and come back to it. That is worth having because 10 questions — 20 in the daily — can take a few minutes, and stopping does not change what those questions are. A level and a daily are held in separate slots, and one never overwrites the other.
• Stopping at question 7 means starting again at question 7. Digits you were part-way through typing are not kept, so that question comes back with an empty blank.

Neither the clock nor the wrong-answer count is shown while you play. Both are recorded and appear when you finish, and in your statistics. A wrong answer is not signalled by colour either — the input clearing is itself the message.

The three shapes of question

Every question takes one of three shapes. Which of them can turn up depends on where you are on the ladder.

• A subtraction never goes negative, and a division always comes out exact. Neither is a filter applied afterwards: the question is assembled from numbers that already satisfy it.
• A chain is read strictly left to right, and every step along the way stays at 0 or above. × and ÷ are never mixed into a chain — that would ask whether you know the precedence rules, which is a different question from whether you can do the arithmetic.
• A missing-number question has exactly one answer. The blank is always the right-hand term, and the two numbers you can see pin it down.
• No question is a non-question. A multiplication has 2 or more on both sides, and in a division both the number you divide by and the result are 2 or more, because 1 × 6, 9 ÷ 1 and 9 ÷ 9 ask nothing.

What guarantees all of this is that a question is only ever assembled in a form that satisfies it — nothing is generated and then thrown away. The tests confirm that across a wide deterministic sample of every level, 200 draws each, which is a check rather than an exhaustive proof, and the difference is worth stating. The one exception is the uniqueness of a missing number: for every question in that sample it is tested against every value the keypad can enter, 0–999.

The 100 levels and the Daily Challenge

Levels run 1–100 and unlock in order — clearing one opens the next, and that is the only condition attached to any of them: no game feature is ever behind an ad or a purchase.

Any level you have unlocked can be picked again at any time, and it is always the same 10 questions. Every set is built on your device from a seed tied to its number, so level 37 is the same level 37 for everyone, and nothing has to be downloaded to make that true.

• Levels 21–30 are the times table itself, held at 2–9 × 2–9 for all 10 of them before the numbers begin to grow at level 31. That stretch is what a child practising multiplication is here for, and it is given room.
• Elsewhere the ceiling on the numbers climbs across a band, from its first level to its last. The range then steps back down when the band changes — a new sign is already a jump in difficulty, and bigger numbers on top of it would be two jumps landing at once.
• Each level records one thing: your fastest clear. Fewest wrong answers is not kept as a record, because a fewest-mistakes best is won by answering slowly, and keeping it would quietly tell you which of speed and care the game wants.
• The Daily Challenge is one set a day of 20 questions, at a difficulty that never moves: all four signs and missing numbers, with the left-hand number capped at 30 and the right-hand one at 9. No weekday is harder than another.
• The last 30 days stay open with nothing to unlock first, so a day you missed is still there to play. The days you finish are recorded, and no streak is counted or shown anywhere.
• The daily is not defined by borrowing a level number. The ladder gives whole bands to one sign at a time, so "the same as level 50" would mean 20 divisions in a row — and re-tuning the ladder later would silently change days that already have times recorded against them.

Those five names are also how your statistics are grouped. Each band keeps its own sets played and cleared, fastest clear, wrong answers in total and total play time, and the daily is counted in a section of its own, so a 20-question day never competes with a 10-question level for a record. Beside them the game keeps how far up the ladder you have reached and how many levels are finished — and no score at all, anywhere.

Getting faster

The one record a level keeps is time, so improving it is about removing hesitation rather than rushing. Most of what follows is simply knowing in advance what a question can and cannot be.

• Work the answer out before you touch the keypad. A 1-digit answer is judged on the first tap, so there is no moment in which to correct it. Deciding first and typing second costs nothing.
• Use the blank as a check. It is already sized to the answer, so if what you are about to type is longer or shorter than the box, work it out again before you tap.
• A missing number is always the right-hand term, which makes the move mechanical: 7 + ? = 15 is 15 − 7, 20 − ? = 14 is 20 − 14, 6 × ? = 42 is 42 ÷ 6, and 36 ÷ ? = 4 is 36 ÷ 4.
• Chains need no precedence. They read left to right and never contain × or ÷, so 12 + 7 − 9 is 12 + 7, and then take away 9.
• A chain never dips below 0 on the way through. If a step of yours comes out negative, that is a slip rather than a hard question — go back one step instead of pressing on.
• A division always comes out exact, wherever it appears, and neither the number you divide by nor the result of dividing is ever 1. A remainder means a mistake somewhere, not a trick.

Questions people ask