that checks out

ABOUT THIS GAME

You know the answer. Can you make the calculator reach it?

that checks out is a single-player math puzzle game about building expressions with a limited supply of calculator keys. Each puzzle gives you a target and an inventory of digits and operations. Choose what to use, decide where to put your parentheses, and find a way to make it all check out.

A calculator with limits

You can’t simply type whatever answer you need. Each digit and operation has a limited number of uses, and some keys won’t be available at all. Join digits into larger numbers, rearrange operations, or build an unexpected fraction to reach the target.

You don’t have to use every key. Later puzzles include spare digits and distracting operations, leaving you to decide which tools matter. Different expressions can reach the same answer, and valid solutions are accepted automatically.

Start small. Think bigger.

Begin with addition, subtraction, multiplication, and division. Solving puzzles unlocks further categories and calculator tools, including factorials, powers, indexed roots, mathematical constants, and functions.

The challenges grow from small arithmetic targets to large numbers and expressions that reward a useful mathematical insight. A huge target might come from a surprisingly small factorial input; an awkward fraction might become useful when turned upside down.

Several puzzles are available within each unlocked category, so you can switch to another problem while you think.

Make room to work

Drag the calculator aside and use the background whiteboard as a scratchpad. Write out ideas with the pen, erase individual marks, and undo or redo your notes.

If you get stuck, Slip, your calculator’s hint-printing companion, offers progressively more direct hints. Print a clue when you need one, then return to experimenting.

Features

• A campaign spanning arithmetic and scientific calculator puzzles.

• Limited-use digits, operations, and parentheses.

• Category progression that introduces additional calculator tools.

• Automatic solution checking, expression undo, and saved puzzle progress.

• A drawable whiteboard with an eraser and undo/redo.

• Progressive hints from a small companion printer.

• Mouse and keyboard input, light and dark themes, and adjustable sound volume.