Expert Calcudoku
Expert Calcudoku puzzles are 6×6 with larger cages and fewer one-cell clues. They need a contradiction: try a digit, follow the cages a few steps, and if a rule breaks, cross it out.
Expert puzzles need at least one of these techniques, and may use any easier one:
- Contradiction
- Try another digit in the marked cell and a rule breaks a few steps later. So that digit is out.
How to play
Calcudoku is an arithmetic logic puzzle on a square grid. Fill each row and column with the digits from 1 up to the grid's size, once each. Thick outlines group cells into cages, and each cage's digits must make the number in its corner using the operation shown: add, subtract, multiply or divide.
Every Calcudoku here has exactly one solution and can be solved by logic alone. The grid grows from 4×4 at Easy to 6×6, and the level is set by the hardest technique the puzzle needs.
- Each row and each column holds every digit from 1 to the grid size once.
- A cage's digits make its number with its operation: + adds, × multiplies.
- − and ÷ cages have two cells and work in either order, larger digit first.
- A one-cell cage simply shows its digit; digits may repeat within a cage if they are in different rows and columns.
Playing on this site
- Select a cell, then type a digit or tap it on the number pad. Arrow keys move the selection.
- Turn on Notes (or press N) to pencil in candidates instead of answers.
- Hint first points out any wrong digits, then names the next technique and shows where it applies before giving anything away.
- Your puzzle is saved in this browser, so you can come back to it later.