Math Puzzles Explanation

Math grid puzzles — finding the missing number

You see a grid of numbers joined by plus and minus signs. Every row and every column forms a valid sum. Some cells are hidden and one carries a question mark.

Step 1. Find a row or column with only one missing number — you can compute it directly.

Step 2. Fill it in and see which row or column now has a single unknown left. Work step by step towards the question mark.

Step 3 — verify. Your answer must work in both directions: the row and the column of the question mark. If one fails, the error is earlier in your chain.

Tip. Mind the minus signs: order matters (8 − 3 is not 3 − 8). Scratch paper is almost always allowed.