Mathle

One hidden equation a day, typed on a pad that offers the ten digits, a plus and a minus. The board carries five rows, each ending in an equals sign. The saved game state spells out the shape it expects: a two digit number, a sign, a second two digit number and a three slot result, which bounds the puzzle before you type a thing.

1. Build an equation with the on screen pad, which carries the ten digits, a plus and a minus.
2. Press DEL to take a character back, Enter to submit the row.
3. Read what the row comes back with, then use the next of the five rows.

Mathle keeps the arithmetic deliberately small. Two digit numbers, one sign, no multiplication, which means the puzzle is never really about calculating: it is about where the digits sit. Five rows is a tight budget for that, and the missing operator keys hand you the whole search space before you start.

The board sat behind the consent dialog for the whole run, so no submitted row and no tile colour was seen. What the game saves points to a colour coded verdict: the stored settings object carries an enableColorBlind flag next to the language, which implies an accessible palette for anyone who needs one. Neither the palette nor what each colour means was observed.

Daily

One puzzle a day. The saved state is keyed by a game number, 1674 on 25 August.

• There is no multiply or divide key on the pad, so the search space is additions and subtractions only. Spend the first row probing digit positions rather than operators.
• The row shape is fixed at two digits, a sign, two digits and a three slot result, so you know how big the numbers can get before the first guess.