What is the least common multiple (LCM)?
The least common multiple (LCM) of two or more numbers is the lowest number of which your starting numbers are all factors. How is it calculated? You begin by splitting your starting numbers into their prime factors. You then go through and for each prime factor, you take the highest power of that factor. For example, using 924 = 22 x 3 x 7 x 11 and 3080 = 23 x 5 x 7 x 11 from before, we take 23, 3, 5, 7 and 11. Therefore the LCM is given by 23 x 3 x 5 x 7 x 11 = 9240. Alternatively, if you have the two numbers and their HCF, you can calculate the LCM by multiplying the two numbers together and then dividing by the HCF. Why is the LCM useful? The LCM proves itself useful when adding or subtracting fractions. When adding or subtracting fractions, you need to calculate the lowest common denominator, which is given by the LCM of all the denominators. Are the an infinite number of prime numbers? Yes. And there is a nice simple proof to go with it. Begin with a prime number… 11 Then multi
