Question: what is the greatest common factor of 1 and 3?
Answer: Enter GCF or LCM numbers: Number 1. ... 
Determine the factors for 3 up to 1 since that is the minimum of the 2 numbers. ... 
Determine the factors for 1 up to 1 since that is the minimum of the 2 numbers. The greatest common factor between them is 1. ... 
Greatest Common Factor and Least Common Multiple Video. MathCelebritydotcom.