GCF and LCM

If you haven't already please look up the Sieve of Eratosthenes!  It is very helpful when deciding whether or not a number is prime.


As we begin to discuss GCF and LCM word problems it is important to make sure that we are comfortable with determining the GCF and LCM of 2 or more numbers using the appropriate strategies.  Unless otherwise stated you can always use the strategy that works best for you HOWEVER it is important to know how to use other strategies as well.  If you are having trouble using prime factorization: practice! and watch video tutorials!










To CHECK your answers (not get your answers) there are actually GCF and LCM online tools that will produce the GCF and LCM of any 2 numbers in seconds.  Pretty awesome, I know!  The links are below along with some helpful video tutorials.


Prime Factorization Tool
GCF Tool
LCM Tool
LearnZillion Video
LCM and GCF Word Problems Video