Inequality Sudoku· Advanced

Goal

Fill each row and column with numbers 1 to N without repeats

How to Play

  • Tap an empty cell to select it
  • Enter a number using the keypad below
  • Switch to memo mode to note candidate numbers

Inequality Rule

Numbers must follow the direction of inequality signs (< >) between adjacent cells

OK3>13 > 1 ✓
NG1>31 > 3 ✗

Row & Column Rule

The same number cannot appear twice in the same row or column

OK13241, 3, 2, 4 ✓
NG13343, 3 ✗

Completed Example

  • No duplicate numbers in any row
  • No duplicate numbers in any column
  • All inequality signs (< >) between adjacent cells must be satisfied
2143341212344321>><<<∧∧

Tip

  • Follow inequality chains to narrow down possible values
  • Start with cells that have only one possible number
  • Identify where the largest and smallest numbers must go first

Adults aged 50+ who regularly solved number puzzles showed statistically significant improvements across all 14 cognitive measures including grammatical reasoning and spatial working memory. fNIRS studies also confirmed prefrontal cortex activation during constraint-based puzzles.

  • Number puzzles and 14 cognitive measures in adults 50+ (Int J Geriatr Psychiatry, 2019)
  • Prefrontal cortex activation during constraint puzzles via fNIRS (PMC, 2020)