My favorite way to find the GCF is using a factor tree. WE take a number a break it down until all the numbers are at the smallest possible and are prime. A good way to practice is to take a large number and break it down without using a calculator and finding all it's prime numbers.
Here is an Example:
Here we can obviously see all the prime numbers within 120 and 96. If we were to find the GCF between the two numbers we will line them up as so:
96: 2 2 2 2 2 3
120: 2 2 2 3 5
Take what numbers are lined up: 2 * 2 * 2 * 3 = 24; Therefore the GCF between 96 and 120 is 24. :) I love the way that this system shows how to find that so easy!
Now, to find the LCM between 96 and 120 is to take all numbers that represnted (only take them once!) and multiply together:
2 * 2 * 2 * 2 * 2 * 3 * 5 = 480! This is a way that we can use so much easier than actually going through every single multiple until we reach the same number. Getting to 480 would have taken so much longer if we did not use this method. :)
Wow, Rachel. It's kind of fun to read about math when I hear your voice in my head. :)
ReplyDeleteThis is a very interesting project. I like it! Hm...a music blog next?