solve

 sudoku

   step 1 2 3 4 5 6 7 8 9 10
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A very easy puzzle to get the idea of how sudoku is solved
© Roger Walker
explanations:-
this is step 3


The 8's in c1 and c2 and the 8 in row 9 define the position of the 8 in box 7 at cell c3r7.

 

 

 

The 4's in c8r3, c3r5 and the new 4 we just found in c7r7 define the 4 at c9r6 for box 6.
As before, according to the rules, there cannot be another 4 in the same row of r5 and columns c7 and c8 but there must be a 4 somewhere in box 6.

 
c1
c2
c3
  
c4
c5
c6
  
c7
c8
c9
 
 
 
1		      
6 		   
3		  
r1
 box

1
2
&
3
  -box 1-       -box 2-    
9		 - box 3 
5
r2

     
7 		       
 
r3

9

3		    
2		    
x 4  		  
x 4
7
r4
 box

4
5
&
6
  - box 4 
 
8		 - box 5 -
5 		   
x 4 		- box 6 
x 4
x 4  
r5
   
7 		   
6 		   
1		  
x 4
4
r6
 
x-8
3		  
8 		 
1 		     

9
r7
 box

7
8
&
9

4 		- box 7 
x-8
5		  
6		 - box 8    
  		box 9 
 
 
r8
 
x-8
6
x-8 		 
9

4 		 
5
 
 
r9




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15th january 2010 © 2014