The numbers from 09 are here represented as they appear in digital clocks:
__ __ __ __ __ __ __ __
   __ __ __ __ __  __ __
__  __ __  __ __  __ __
An example of a multiplication (a 2digit number by an 1digit 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 3digit by 3digit multiplication below?
__ __
 
 
x __
 __
 __

  
__   
__
   __
 __
  
 __   __

__
 __  __  
   __ __
Can we assume that each of the three intermediate products is actually 4 digits long, i.e., no leading zeroes?

Posted by Charlie
on 20050809 20:03:41 