Save guides, add subjects and pick up where you left off with your BBC account. The highest common factor (abbreviated to HCF) is the largest number that goes into two or more subject-numbers.

Refresh your knowledge with these guides on factor trees and writing numbers as a product of prime factors. List the factors of each number. Compare the lists to find the greatest number common to ...

Starfleet's Prime Directive states that official ... allowed for interstellar exploration and trade. Warp factor 10 is meant ...