World's Hardest 4x4 Micro Sudoku : r/sudoku

Logical Thinking Puzzles: 4×4 Sudoku Teaching London Computing: A RESOURCE HUB from CAS LONDON & CS4FN

1200 Easy Sudoku for Kids 4x4 - Bundle Graphic by PrintablePDFStore · Creative Fabrica

Two 4x4 sudoku for kids to print: Level Beginner, No. 1 and No. 2.

Math Sudoku Puzzles Digital Download Easy Level 4x4 Grid: 300

Handwriting for Kids - Picture Sudoku

Kids Sudoku 4x4 - Medium

4x4 to 6x6 Easy SUDOKU Puzzle by Kozo Terai

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I hired a developer to create a sudoku generator for me. It generates 4x4, 6x6 and 9x9 with the difficulties easy, medium, hard, very hard. This is from a 6x6 very hard

The Big Book of Kindergarten Sudoku : 4x4 Sudoku and Wordoku Puzzles for Kids by J. Green (2017, Trade Paperback) for sale online