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In this 4 by 4 Mathematical Sudoku, you need to use the clues available to fill the sixteen cells.
Clicking on the purple cog in the top right corner allows you to access twelve different puzzles at different levels of difficulty.
If you are not familiar with Mathdokus, you may like to watch this introductory video, which gives you some ideas of the strategies you may find useful.
This Mathdoku belongs to a set, which also contains 3 by 3, 5 by 5 and 6 by 6 grid sizes.
If you would prefer to work away from the computer, you can print out these grids: Mathdoku grids of difficulty 1, Mathdoku grids of difficulty 2, Mathdoku grids of difficulty 3.
NRICH would like to thank Tetsuya Miyamoto, a Japanese maths teacher, whose puzzles have inspired our Mathdokus.