# sudoku

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explanations:-
this is step:- 17

Work down boxes 2, 5 & 8 filling in all the possible values for each empty cell.

This finds 4 and therefore 9 in box 2 leaving only 8 & 3 for the last two cells

As we have found 4 in box 2 above, c5/r6 must be 2.
Therefore the last two cells in box 5 must be a 3 or 4.

It follows that row 5 in box 6 cannot have a 3 or 4 so it must be 5. The last cell in box 6 at c9r6 is therefore 4.

c1
c2
c3

c4
c5
c6

c7
c8
c9

 279
3
 6 279
5
 4
4
 4  9
9
8 1
r1
box

1
2
&
3
1
 258
 258
7
 box 2
6
 8 34

 box 3
9
r2
4
 578
 6 5789
2 1
 8 9 3

r3
8 4 3   9 7 5   1 2 6
r4
box

4
5
&
6
 9 25
 box 4
1
 9 25
6
 3 24
 3 4

 4 5
5
 box 6
7
8
r5
6
 7 25
 7 25
8
 24
2
1   9 3
 4 5
4
r6
 23
 8 2
 24  8
1 5 7
 6
 6
9
r7
box

7
8
&
9
 2375
 box 7
9
 4  257

 3 4
 box 8
8
6
 box 9
1
r8
 357
6 1
 3 4
9 2   8
r9
 ___________________________________ [ contact me, Roger Walker ] 15th january 2010 © 2012