About iptsi Sum
iptsi Sum is a mental arithmetic game with a clock. A sum appears, four answers are offered, and a bar drains while you decide. Answer correctly and you score; answer wrongly or let the bar empty and you lose one of your three lives.
The difficulty is staged in three steps. The first is simple addition with small numbers, the second mixes in subtraction with numbers in the tens, and the third introduces multiplication and longer subtraction. Each step up happens after six correct answers, so a good run is rewarded with genuinely harder arithmetic rather than just less time.
How to play
- Read the sum and tap the answer you think is right.
- A correct answer scores and starts the next sum; the time bar refills each time.
- A wrong answer costs a life, and so does running the bar down to nothing.
- Three lives lost ends the run.
How it was built
The sum, the buttons and the bar are drawn at runtime on one canvas, so the game needs no images and no fonts to fetch, and the correct and incorrect tones are generated with the Web Audio API. It is a single HTML file that makes no network request and works offline.
The wrong answers are not random. Each is generated close to the correct value — usually within a few either side — because a multiple-choice question with one obviously wrong option is not a question. The distractors are what make the arithmetic worth doing.
Why it is free
iptsi builds these games in-house and owns the code and the artwork outright, so nothing has to be licensed or attributed. They are here to be played, and to show the sort of title that suits the open web: instant, offline, and readable on a small screen. There is no account, no download and no advertising on this page, and your best score lives in your own browser.