solve

 sudoku

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explanations:-
this is step:- 22

 

Note 2
The last cell in col 1 must be a 2. The new 8 in box 7 makes a 5 in c3/r2 and so an 8 next door.
Just one cell left for 7

Note 3
With the 7 & 5 in box 1 defined, box 4 can be finished

Note 1
The new 4 in box 9 makes the 8 in box 7, then the 2, then the 3. Below the 3 must now be a 7 with the 2 and 3 gone and the last cell a 4. This 4 decides the 3 & 4 in box 8 and the 2 in box 9, the last in row 8

c1
c2
c3
 
c4
c5
c6
 
c7
c8
c9
 
27 
2
 
3
 
6
 
 
5
 
4
 
9
 
 
8
 
1
 27
r1
box

1
2
&
3
 
1
258 
8
258 
5
 
 
7
box 2 
6
8 3
 
234 
4
box 3 
9
235 
r2
 
4
578 
7
 
9
 
 
2
 
1
 8 3
 
 367
 56
6
357 
r3
 
8
 
4
 
3
 
 
9
 
7
 
5
 
 
1
 
2
 
6
r4
box

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

7
8
&
9
2375 
7
box 7 
9
4  257
4
 
3 4
3
box 8 
8
 
6
 
2347 
2
 
5
 
1
r8
357 
5
 
6
 
1
 
 3 4
4
 
9
 
2
 
347 
 
8
357 
r9



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15th january 2010 © 2014