When we work with LCM, we are trying to find the smallest, shared multiple. To do that, we work backwards through the letters, first finding the multiples of the numbers we are given. You can and should use the pink multiplication chart that I gave you in class today to find multiples if you need it. Then begin to identify what numbers they share. You can see in the top example in the picture below that 2 and 8 share the multiples, 8, 16, 24, 32, 40.... (and many others).
Finally, we look to see what the smallest of the shared multiple is to identify the LCM. You can see that with 8 and 2, the LCM is 8! When we compared 15 and 16, the LCM is 240 because there isn't anything smaller. Sometimes you can multiply the two numbers to see what multiple they definitely share, but you need to be careful that there isn't a smaller one. For example, #22 on tonight's homework gives us the values 11 and 33. 11 X 33 = 363, but the LCM is much much smaller! The multiples of 11 are 11, 22, 33, 44, 55, 66... Wait a minute... 33? 33! 33!!!!! We already found our LCM!!!
Now, when do we use LCM is real life? People aren't going to come up to you randomly in real life and ask you for the LCM of 6 and 4, but your schedule may say that you have Lunch with a teacher every sixth day and Jazz band every fourth day and you want to find out how often you have both the same day! Here are the examples we completed in class today! (Thanks to Green class for allowing me to use your work!)
Tonight's homework is to finish the class sheet if you didn't finish in school. The problems are below, so if you lost the paper, just print out the image below!
I know that not everyone got a chance to play the online game that I shared in class. If you want to play, just click here!!!
Have a lovely weekend! See you Monday!
-Miss K :)