Answer Does Not Match? Causes & Fixes
When your Sudoku answer does not seem right, here are the common causes and solutions.
3 Common Causes
Cause 1: Duplicate Overlooked
Check if the same number appears twice in any row, column, or block. Duplicates near block boundaries are especially easy to miss.
→ Scan each number across its row, column, and block. Mistakes are highlighted in red — check those cells.
Cause 2: Wrong Candidates
If your pencil marks are wrong, all subsequent reasoning will be off.
→ Update candidate numbers in surrounding cells every time you place a number. Make it a habit.
Cause 3: Illusion of Multiple Solutions
Sometimes it feels like "it could go here or there," causing confusion.
→ Instead of asking "where can this go?" ask "where must this go?" — focus on forced placements, not possibilities.
Habits to Prevent Mistakes
- ✅ Always check the row, column, and block before placing a number
- ✅ Update candidates in affected areas after each placement
- ✅ Take breaks when tired — fatigue leads to mistakes