Cipher (Mind Loft)

Cipher serves one alphametic a day: an addition written in letters, where each letter stands for a different digit. Work out the digits so the arithmetic holds. Each equation is machine-checked to have exactly one solution, so careful column reasoning always gets there without guessing.

The board does the bookkeeping that would otherwise need paper. The digit pad dims a digit as soon as another letter uses it and shows which letter has it; the carry row above the equation fills itself in as far as your digits allow; and each column shows a tick or a cross the moment it is decided, so a wrong digit shows up where it happened. A Notes mode lets you pencil in candidate digits, and the code book beside the sum marks which letters start a word and so cannot be 0. There is no submit button: the puzzle locks as soon as your assignment is right.

A solve scores a perfect 10, so the leaderboard is a race on the clock; revealing the answer ends the day at 0. The difficulty ramps through the week, with two addends Monday to Wednesday, three Thursday to Saturday and four on Sunday. A new equation arrives every day at midnight Eastern.