The LCF, or Lowest Common Factor, of 3 and 5 is 15. This is because 15 is the smallest number that both 3 and 5 can divide into evenly. In other words, 15 is the smallest multiple that is common to both 3 and 5.
Well, honey, the LCF of 3 and 5 is simply 15. It's the smallest number that both 3 and 5 can divide into evenly. So, there you have it - 15 is the magical number that brings these two together in perfect harmony.