How do you find the GCF of 20, 21 and 25? Prealgebra Factors and Multiples Greatest Common Factor 1 Answer sjc Jan 9, 2017 1 Explanation: factors: #20:{1,2,4,5,10,20}# #21:{1,3,7,21}# #25:[1,5,25]# #GCF =1# Answer link Related questions What's the GCF of 3 and 5? What is the GCF for 54, 72? What is the GCF of 36 and 60? What is the GCF of 2, 5, and 6? What is the GCF of 18 and 30? What is the greatest common factor of 175 and 245? What is the greatest common factor of 108 and 168? How do you find the GCF and LCM of numbers? What is the GCF of 210 and 252? What is a GCF? See all questions in Greatest Common Factor Impact of this question 2793 views around the world You can reuse this answer Creative Commons License