The numbers from 0-9 are here represented as they appear in digital clocks:

     
    __         __     __            __     __   __     __    __ 
   |  |   |    __|    __|   |__|   |__    |__     |   |__|  |__| 
   |__|   |   |__     __|      |    __|   |__|    |   |__|   __|

An example of a multiplication (a 2-digit number by an 1-digit number) unidentified because some "LEDs" failed and are "off" (they had to be "on") is shown at left, and the correct one is shown at right (the alignment is perfect):

                                            __     __
                     |                      __|   |__|
           |                               |__    |__|
                                                   __
                                                  |__| 
            x     |                         x     |__|
   -------------------              ------------------
            __                       __     __    
       |    __       |               __|    __|   |__|   
    |      |         |              |__    |__       |

Can you "turn on" the failing "LEDs" in the 3-digit by 3-digit multiplication below?

                                          __     __
                                  |                |
                                  |      |     
                            x      __            
                                     |    __      
                                            |   |__
                            ------------------------
                                                 
                                  |  |      |   
                            __|             |   |  | 
                            __            
                       |   |         |    __|
                    |              __    
                                   
                |      |          |
                |    __    |  |    __ 
             ---------------------------------------
                                                 __
                |    __       |    __    |  |   
                |   |         |    __            __

(In reply to can we assume by Charlie)

Yes, Charlie, no leading zeroes in all numbers.

Posted by pcbouhid on 2005-08-09 20:14:39