Thursday's Class

I hope you all are enjoying Raven's Day!

Please get with your partner and check your work from yesterday (pg. 193, 9 - 16). Here are the answers:

9.  23	10.  72	11.  2 · 17
12.  2 · 3 · 7	13.  23 · 32 · 5	14.  5 · 23
15.  2 · 3 · 31	16.  33 · 23

Now with your partner, read the rest of section 4-3 (pgs. 191 and 192). I know that using Prime Factorization to find the Greatest Common Factor (or "GCF") can be very confusing, which is why I'm going to show you another way. First, look at how they find the GCF at the bottom of pg. 191. By breaking down each number (or expression - as in the expressions with the variables) to its prime factors, we are then able to find out which prime factors they have in common. Then, multiply those factors together to find the GCF. For example:

The prime factorization of 18 is 2 x 3 x 3. The prime factorization of 30 is 2 x 3 x 5. Since both prime factorizations contain a 2 and a 3, multiply 2 and 3 together to get 6. We know now that 6 is the GCF of 18 and 30.

There's another way to find the GCF, however, and it's a bit easier as long as you're not dealing with crazy big numbers. Watch the following video with your partner. In this video, the GCF is referred to as the "Greatest Common Divisor" - they are the same thing. Then try a few of the exercise questions after the video. If you have earbuds, please use them:
https://www.khanacademy.org/math/arithmetic/factors-multiples/greatest_common_divisor/v/greatest-common-divisor

Now, with your partner, try pg. 193, 17 - 24. You can use either method, but for 21 - 24, finding the prime factorization first might help. These are very tricky, but try to help each other when solving these. SAVE YOUR WORK and put it somewhere safe. Tomorrow when you check your work I will be walking you through GCF for variable expressions step by step, but for now I'd like you guys to try it after reading the textbook. Please let me know how you do. Are you guys able to comment on these posts?