Fill in the boxes using each digit from 1 to 9 once so that each equation is correct. Note that all operations are performed in order from left to right or top to bottom.

  _     _     _
 |_| x |_| - |_| = 6 

  +     +     +
  _     _     _
 |_| + |_| - |_| = 5 

  -     x     /  
  _     _     _ 
 |_| x |_| / |_| = 3 

  =     =     =
  2     9     4

(In reply to thinkigotit by Wallace North)

Yep, that's what I got too.  I won't go through the whole process, but here's a start...

Label the 9 missing digits as:

A B C
D E F
G H I

A good place to start is with H.  You know that (B+E)*H = 9, so H must be either 3 or 1.  If H was 3, then G and I would have to be the same number, which is not allowed.  Therefore, H is 1.

Going across, G*1/I = 3, so either G=6 and I=2, or G=9 and I=3.  If I=2, then C+F would have to equal 8.  But this would mean that C & F were 5 & 3 (in some order).  A quick inspection shows that this is impossible (try plugging 3 for C or F and solve the row, it's impossible).  Therefore, G=9 and I=3.

Etc.

Posted by tomarken on 2006-03-28 10:42:00