Find two numbers such that 
.
If you know the greatest common divisor
of 
and 
, there exists a high probability of determining a prime
factor. Taking small numbers 
which additionally give small primes 
further increases the chances
of finding a prime factor.
Prime Cut
See also
Greatest Common DivisorExplore with Wolfram|Alpha
Cite this as:
Weisstein, Eric W. "Prime Cut." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/PrimeCut.html