A puzzle cabinet has four number panels. Two add. Two multiply. Each looks almost too small to be trouble. The catch? The little letters connect them.
Fill all four panels, then read their center numbers in A, B, C, D order to open the lock.
1. No repeats in a line. Use only 1, 2 and 3. Every row and every column of each square must contain all three numbers exactly once.
2. Follow the arithmetic. Each square has one outlined, shaded pair. In A and C, add those two numbers to reach the target. In B and D, multiply them.
3. Match the letters. The two cells marked w hold the same number. So do the two x cells, the two y cells and the two z cells. Different letters may hold the same number.
Enter 1, 2 or 3. Use Tab to move between cells, or arrow keys within a square. The small letters are labels, not numbers.
ASum = 4
Add the outlined pair
BProduct = 2
Multiply the outlined pair
CSum = 5
Add the outlined pair
DProduct = 3
Multiply the outlined pair
Blank cells await numbers. Small letters are links, not given numbers. Only the outlined pair is used for each arithmetic target. There is no diagonal rule and no extra rule for the combined four-square layout.
Three chances: check a completed set of four squares. A wrong completed submission uses one chance. After the third miss, reset and start the same puzzle again. Editing and incomplete submissions do not use a chance.
Fill all four squares before trying the lock.
Explore a link: see how possibilities narrow
This optional reasoning aid compares the two cells with the same letter. It uses your entries and each square's own rules, not a hidden answer. It never fills a cell or uses a chance.
These possibilities depend on your working entries. They are not confirmation that those entries are correct.
Show a small hint
First use each arithmetic pair to find the missing number elsewhere in its row or column. Then look at w in A and B. Which numbers are still possible in each cell? Keep only the number that works in both.