Guess the hidden equation
A maths twist on the word-guessing craze. A hidden equation — something like 12+34=46 — fills a row of eight tiles. You have six guesses to crack it, and every guess you type must itself be a true equation. After each one the tiles light up: green where a number or sign is exactly right, purple where it belongs in the equation but sits in the wrong spot, grey where it isn't used at all. Read the clues, narrow it down, and solve. Each puzzle you crack extends your streak; the moment one beats you, the run is over.
The answer is a valid arithmetic equation spread across eight tiles, using the digits 0–9, the signs plus, minus, times and divide, and exactly one equals sign — for example 12+34=46 or 9×8-2=70.
Tap the on-screen keypad to type a full eight-tile guess, then press Enter. Your guess has to be a true equation in its own right: the part left of the equals sign must actually work out to the number on the right. If it doesn't add up, or you've left tiles blank, it won't be accepted and you can fix it first.
When you submit a valid guess, each tile is coloured. Green means that symbol is correct and in the right place. Purple means that symbol appears somewhere in the hidden equation, but not where you put it. Grey means it isn't in the equation at all. The keypad keys colour in the same way, so you can see what's left.
Use the colours to deduce the hidden equation. You have six rows of guesses. Solve it — all eight tiles green — and you bank the puzzle and move straight on to a new one, growing your streak. Fail to crack it within six guesses and the answer is revealed and your run ends.
Open with a guess that uses many different symbols. Just like the word version, your first row is reconnaissance: cram in a spread of digits and at least a couple of operators so the colours rule out as much as possible. An equation packed with 1s tells you very little.
Pin down the operators early. There are only four signs plus one equals, so working out which operations the equation uses — and roughly where the equals sits — collapses the possibilities fast. A green or purple on a sign is worth a lot.
Remember order of operations. The hidden equation follows standard maths: multiplication and division happen before addition and subtraction. When you reconstruct candidates, evaluate them the same way, or your 'valid' guess will be rejected.
Let the keypad colours do the bookkeeping. Greyed-out keys are gone for good, so stop trying them. Purple keys must appear somewhere you haven't placed them yet — shuffle those known digits and signs into new positions instead of guessing fresh ones.