Clue numbers at 17pt, 15.7mm spacious cells, and 500+ machine-verified Calcudoku challenges with room in the margins to work out your factors.
Spacious boxes with room in the margins to comfortably work out your factors.
High-contrast geometric numbers — never guess + from ÷ again.
110 full-sized 8.5" × 11" pages graded by technique with full-size answer keys.
Exactly one solution, every time. Rigorously machine-verified algorithms.
Fill the 4x4 grid so every row and column contains numbers 1, 2, 3, and 4 without duplicates. Each outlined "cage" must equal its target mathematical value using +, −, ×, or ÷.
Calcudoku combines the single-digit placement of Sudoku with elementary mathematical operations. Numbers in an outlined cage must combine to produce the top-left clue.
Sum of all cells in this cage must equal 7 (e.g. 4 + 3 or 1 + 2 + 4).
Product of all cage cells equals 12 (e.g. 3 × 4 or 2 × 2 × 3).
Difference between 2 cells equals 2 in any order (e.g. 4 − 2 = 2 or 3 − 1 = 2).
Larger cell divided by smaller cell equals 2 (e.g. 4 ÷ 2 = 2 or 2 ÷ 1 = 2).
Pro Tip: Numbers can repeat within the same cage if they are in different rows and columns (e.g. in an L-shaped cage), but never within the same row or column!
Choose from Math & Cage Logic, Classic Sudoku & Word Challenges, Junior STEM Workbooks, or Senior Comfort Extra Large Print.
Prefer solving on your iPad/Apple Pencil, Android tablet, or printing unlimited sheets at home? Get high-resolution vector PDF bundles delivered instantly with verified answer keys.
600 Calibrated easy-tier grids for smooth daily warmup and stress reduction.
1,200+ Grids spanning 4x4, 5x5, 6x6, 8x8, and 9x9 extreme grandmaster levels.
450 Giant 24pt grids engineered specifically for maximum visibility and eye comfort.
We rebuilt the logic puzzle book standard from scratch to eliminate eye fatigue, formatting errors, and unfair guessing requirements.
Zero eye-strain grid rendering. Thick black cage outlines, sharp mathematical operators, and wide margins specifically engineered for comfortable, strain-free solving sessions.
100% accurate, single-solution logic grids. Every single puzzle is rigorously verified by proprietary solver algorithms to ensure pure deductive reasoning without ambiguous dead-ends.
Gradual difficulty ramps from beginner warmup to grandmaster. Each volume guides you through calibrated cognitive hurdles so you develop mathematical intuition naturally.
Unlike passive puzzles or repetitive word games, Calcudoku exercises both halves of your brain simultaneously: combining spatial deduction in the parietal lobe with working memory and arithmetic calculation in the prefrontal cortex.
Just two to three grids with your morning coffee provides sustained cognitive alertness throughout the day.
Experience the Brain Focus™ quality standard at home. Includes 4x4, 5x5, 6x6, and 8x8 sample grids, our cage math strategy manual, and full verified answer keys.
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