Try factoring the number.What two-digit numbers have a product of 6,789?
We have tried multiplying numerous numbers. . . . . quite possibly the WORST method!
We see that it is divisible by 3: .
Then we try dividing by consecutive primes (3, 5, 7, 11, 13, ...)
. . to determine other factors.
It takes a while, but we find that: .
. . Hence: .