Question

Solve the following 4 × 4 Sudoku.
(3 marks)

Answer 1

The solution for above sudoku is,

Explanation,

• For fillinng sudoku we can start from that row and column which has maximum number of entries.
• But here we have same number of entries in each row and column.

So, let's start with first 2 × 2 grid. Here we can see 2 and 4 are already present.

• In first grid where 2 is present there we cannot enter 1 because it is presented in that coulumn.
• So in row of 2 we will enter 1.
• It's now clear that in first grid only left number is 3 which will be filled in first blank. (1 mark)

Now we have few entries so with the help of that other can be easily solved.

• So in first column we have the value 3,2 and 1 so only left value is 4.
• In second column we have 1, 3 and 4 so only left value is 2.
• In first row 2, 3 and 4 are filled so only left value is 1. (1 mark)
• In last column last 1, 3 and 4 is filled so only left value is 2
• In second row1,2 and 3 are filled ony left value is 4.
• In third row 1,2 and 4 is filled only left value is 3. (1 mark)