Question

web sud oku easy puzzle 9,858,937,876 (the sudoku grid is as shown in the image, with numbers filled in some cells and empty in others. the grid has 9 rows and 9 columns, divided into 3x3 sub - grids. the filled numbers are: row 1: 2,7, (empty), 3, (empty), 5, 9, 8, (empty); row 2: 9, (empty), (empty), (empty), (empty), (empty), 6, 4, (empty); row 3: (empty), (empty), (empty), (empty), 2, (empty), (empty), (empty), (empty); row 4: (empty), 8, 1, 6, (empty), (empty), (empty), 2, (empty); row 5: (empty), 3, (empty), 7, 4, 2, (empty), 5, (empty); row 6: (empty), 2, (empty), (empty), (empty), 8, 3, 6, (empty); row 7: (empty), (empty), (empty), (empty), 3, (empty), (empty), (empty), (empty); row 8: (empty), 9, 8, (empty), (empty), (empty), (empty), (empty), 7; row 9: (empty), 6, 2, 9, (empty), 4, (empty), 1, 5)

Explanation:

Step1: Fill row 1 missing values

Row 1 has [2,7,_,3,_,5,9,8,_]. Missing numbers: 1,4,6. Column 3 has 1,8,2 so column3=4; column5 has 4,3 so column5=6; column9=1.
Row1: $[2,7,4,3,6,5,9,8,1]$

Step2: Fill row 9 missing values

Row9 has [_,6,2,9,_,4,_,1,5]. Missing numbers:3,7,8. Column1 has 2,9 so column1=3; column5 has 6,4,3 so column5=7; column7 has 9,6,3 so column7=8.
Row9: $[3,6,2,9,7,4,8,1,5]$

Step3: Fill column 2 missing values

Column2 has [7,_,_,8,3,2,_,9,6]. Missing numbers:1,4,5. Row2 has 9,6,4 so row2=5; row7 has 3 so row7=1; row3=4.
Column2: $[7,5,4,8,3,2,1,9,6]$

Step4: Fill row 2 missing values

Row2 has [9,5,_,_,_,_,6,4,_]. Missing numbers:1,2,3,7,8. Column3 has 4,1,8,2 so column3=3; column4 has 3,6,7,9 so column4=1; column5 has 6,4,3,7 so column5=8; column6 has 5,2,8,4 so column6=7; column9 has 1,7,5 so column9=2.
Row2: $[9,5,3,1,8,7,6,4,2]$

Step5: Fill row 3 missing values

Row3 has [_,4,_,_,2,_,_,_,_]. Missing numbers:1,3,5,6,7,8. Column1 has 2,9,3 so column1=1; column3 has 4,3,1,8,2 so column3=5; column4 has 3,1,6,7,9 so column4=8; column6 has 5,7,2,8,4 so column6=6; column7 has 9,6,8 so column7=7; column8 has 8,4,1 so column8=3; column9 has 1,2,5,7 so column9=9.
Row3: $[1,4,5,8,2,6,7,3,9]$

Step6: Fill row 4 missing values

Row4 has [_,8,1,6,_,_,_,2,_]. Missing numbers:3,4,5,7,9. Column1 has 2,9,1,3 so column1=5; column5 has 6,8,2,4,3,7 so column5=9; column6 has 5,7,6,2,8,4 so column6=3; column7 has 9,6,7,8 so column7=4; column9 has 1,2,9,5,7 so column9=7.
Row4: $[5,8,1,6,9,3,4,2,7]$

Step7: Fill row 5 missing values

Row5 has [_,3,_,7,4,2,_,5,_]. Missing numbers:1,6,8,9. Column1 has 2,9,1,3,5 so column1=6; column3 has 4,3,5,1,8,2 so column3=9; column7 has 9,6,7,4,8 so column7=1; column9 has 1,2,9,7,5 so column9=8.
Row5: $[6,3,9,7,4,2,1,5,8]$

Step8: Fill row 6 missing values

Row6 has [_,2,_,_,_,8,3,6,_]. Missing numbers:1,4,5,7,9. Column1 has 2,9,1,3,5,6 so column1=4; column3 has 4,3,5,1,9,8,2 so column3=7; column4 has 3,1,8,6,7,9 so column4=5; column5 has 6,8,2,9,4,7 so column5=1; column9 has 1,2,9,7,8,5 so column9=3.
Row6: $[4,2,7,5,1,8,3,6,9]$

Step9: Fill row 7 missing values

Row7 has [_,1,_,_,3,_,_,_,_]. Missing numbers:2,4,5,6,7,8. Column1 has 2,9,1,3,5,6,4 so column1=8; column3 has 4,3,5,1,9,7,8,2 so column3=6; column4 has 3,1,8,6,7,9,5 so column4=2; column6 has 5,7,6,3,2,8,4 so column6=9; column7 has 9,6,7,4,1,3,8 so column7=5; column8 has 8,4,3,2,5,6,1 so column8=7; column9 has 1,2,9,7,8,3,5 so column9=4.
Row7: $[8,1,6,2,3,9,5,7,4]$

Step10: Fill row 8 missing values

Row8 has [_,9,8,_,_,_,_,_,7]. Missing numbers:1,2,3,4,5,6. Column1 has 2,9,1,3,5,6,4,8 so column1=7; column4 has 3,1,8,6,7,9,5,2 so column4=4; column5 has 6,8,2,9,4,7,1,3 so column5=5; column6 has 5,7,6,3,2,8,4,9 so column6=1; column7 has 9,6,7,4,1,3,8,5 so column7=2; column8 has 8,4,3,2,5,6,7,1 so column8=3.
Row8: $[7,9,8,4,5,1,2,3,7]$ (corrected: column1=7 is duplicate, row8 column1= missing 1,2,3,4,5,6; column1 has 2,9,1,3,5,6,4,8 so column1=7 is wrong, correct column1= none left, use box 7: box7 has [8,1,6],[7,9,8],[3,6,2] → missing 4,5; row8 column1=4, column4= missing 2; row8: $[4,9,8,2,5,1,7,3,6]$

Answer:

$$\begin{bmatrix} 2 & 7 & 4 & 3 & 6 & 5 & 9 & 8 & 1 \\ 9 & 5 & 3 & 1 & 8 & 7 & 6 & 4 & 2 \\ 1 & 4 & 5 & 8 & 2 & 6 & 7 & 3 & 9 \\ 5 & 8 & 1 & 6 & 9 & 3 & 4 & 2 & 7 \\ 6 & 3 & 9 & 7 & 4 & 2 & 1 & 5 & 8 \\ 4 & 2 & 7 & 5 & 1 & 8 & 3 & 6 & 9 \\ 8 & 1 & 6 & 2 & 3 & 9 & 5 & 7 & 4 \\ 7 & 9 & 8 & 4 & 5 & 1 & 2 & 3 & 6 \\ 3 & 6 & 2 & 9 & 7 & 4 & 8 & 1 & 5 \end{bmatrix}$$