Crab Math Run

Math practice built to keep you playing.

A crab walks a pier over the sea, and the math problem rides inside the sun. Answer it and the parrot flies a plank across the gap. Answer fast and the next problem is already waiting. At the end of the run the boat comes in and presses every shell earned into gems.

The math is real, and you set it • Addition, subtraction, multiplication and division: one sign, plus and minus, times and divide, or all four • Three levels: numbers 0 to 4, 0 to 9, and 0 to 12 • A custom range anywhere from 0 to 20, or one number to drill, like the sevens • Four speeds, from 15 seconds a problem down to 4 • Type the answer on a keypad, or pick from four choices • Every fact in the range comes up once before any repeats

No shame in a wrong answer In Safe mode, the default, a missed problem still gets its plank, with the whole fact written on it, and the hero never falls. The parrot's key stays dark, and play goes on. Splash mode is there for players who want stakes: the boards run out, the hero goes in, and the boat pulls him out with a rope ladder every time. The run ends there, but shells already earned are always paid.

Ways to play • Timed runs of 1, 2 or 5 minutes • Relax, with no clock: the boat comes the moment you call it • Flash cards for pure study, with the answer on the back • Missed: every fact you miss is kept in one list, and two right answers in a row take it off

A sea that grows with every right answer Gems come only from right answers, and they cannot be bought. They dress the pier and the seabed: 11 things for the pier, 10 for the sand, flags for the boat, snails, and food for the fish. Thirteen kinds of sea life join your water as your gems add up. Four super creatures, the Great Orca, the Manta Ray, the Beluga and the Narwhal, patrol the deep, and each one asks a sum of its own when you tap it. A treasure chest on the sand asks one too.

Pick your hero: a crab, an octopus or a snail.

Good to know • One purchase. No in-app purchases, no ads, no subscriptions • No accounts, no sign-in, and nothing is collected. Progress stays on the device • Plays without an internet connection • Every run ends with a summary: accuracy, average answer time, longest streak, and what was earned • The Records book keeps a page for every kind of run

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