solve

 sudoku

  to step 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23
  <home

explanations:-
this is step:- 1


Check for easy results.
1 has to be in c1/r2 because of the 1's in box 3, 4 and 7
.

Remember -
Each column, row and 3x3 box must contain the numbers 1 to 9 so box 1 must have a 1 in it somewhere.

See solution at step 23

c1
c2
c3
 
c4
c5
c6
 
c7
c8
c9
 
 
 
3
 
 
 
5
 
 
 
 
8
 
1
 
r1
box

1
2
&
3
 
1
box 1 
 
 
 
7
box 2 
6
 
 
 
box 3 
9
 
r2
 
4
 
 
 
 
 
 
 
 
 
 
r3
 
 
4
 
3
 
 
9
 
 
5
 
 
 
 
6
r4
box

4
5
&
6
 
box 4 
1
 
 
 
box 5 
 
 
 
box 6 
7
 
r5
 
6
 
 
 
 
8
 
 
1
 
 
9
 
3
 
r6
 
 
 
 
 
 
 
 
 
 
 
9
r7
box

7
8
&
9
 
box 7 
9
 
 
 
box 8 
8
 
6
 
 
box 9 
 
r8
 
 
6
 
1
 
 
 
 
2
 
 
 
8
 
r9



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15th january 2010 © 2014