Sudoku is a popular logic-based puzzle game that can be played online. The game Sudoku 4 in 1 consists of a 9x9 grid, divided into nine 3x3 sub-grids. The objective of the game is to fill each of the 81 cells in the grid with a number from 1 to 9, with each number appearing only once in each row, column, and sub-grid.

Click and hold on the empty cell where you want to place the number. Drag the number to the empty cell and release the mouse button.

Remember that each number can only appear once in each row, column, and sub-grid. So, as you fill in numbers, be sure to double-check that they are in the correct places.