math  8th grade
posted by taylor2008 on .
use the numbers one to nine, each one only once. now multiply a two digit number by a three digit number and get a four digit answer using each of the digits, 19 each only once.
12 x 345 = 6789 of course that isn't a true statement though.

What is 28x157?
http://www.worldofnumbers.com/ninedig1.htm 
thanks mr pursley!

I am curious to know how does one figure this out?
Is there any formula? or just by trialerror method?