GCF and LCM

LCM stands for Lowest Common Multiple, in other words, the smallest number that is a multiple of each number in a set of numbers. 

LCM is helpful for many math operations, including finding a common denominator in fractions. The fastest and most efficient way to find a common denominator is to find the LCM of the denominators.

How do you find a LCM?

For many numbers, if you know your times tables, it's easy to figure out the LCM, it might even be obvious.

GCF stands for Greatest Common Factor, in other words, the largest number that is a factor of a set of numbers. 

GCF is helpful for many math operations, including simplifying fractions. The fastest and most efficient way to simplify a fraction is to divide the numerator and denominator by their GCF.

How do you find a GCF?

For many numbers, if you know your times tables, it's easy to figure out the GCF, it might even be obvious.