Kalkra

Kalkra is a fast, elegant mental-math game built around one simple, endlessly replayable idea: reach the target.

You're given a small pool of numbers and the four operators — +, −, ×, ÷. Combine them to hit the target number. Each number can be used once. Sounds simple. Then the timer starts, the targets multiply, and the operators start disappearing.

Every round is generated fresh and verified solvable before you ever see it, so you're never stuck on an impossible puzzle — only on how fast your brain can find the path.

GAME MODES • Practice — one target, six numbers, no pressure. Learn the ropes. • Endless — starts gentle and ramps up forever. How long can you last? • Progressive — a ladder of twists: forbidden numbers, two targets at once, expanding pools, mandatory numbers, and sudden countdowns. • Tunnel Vision — one target stays fixed while the numbers refresh every round. • Permutations — multiple solutions welcome; find as many paths as you can. • Powers of 2 — a specialized pool and target type for binary brains. • Triple Threat & Double Danger — juggle multiple targets in a single round.

WILDCARD MODIFIERS Speed pressure, operator lockouts, and double-or-nothing scoring drop in to keep you honest.

BUILT TO COME BACK TO • A full career with stats, an Elo skill rating, and unlockable achievements. • Multiple hand-crafted visual themes to make it yours. • [iOS] One responsive design that adapts to the device: a focused portrait layout on iPhone, and the full roomy layout in landscape on iPad — including Split View, where it switches layouts as you resize.

PRIVACY BY DESIGN Kalkra is completely offline. No account. No sign-up. No ads. No in-app purchases. No analytics, no tracking, no data ever leaves your device. Just you and the numbers.

Whether you've got two minutes or twenty, Kalkra turns mental math into something you'll actually want to keep playing.