Prime Factorization

The students started prime factorization this week. 

I was unfortunately sick on Wednesday and ended up missing school that day. It was the first unplanned absence I had in 5 years. It was agonizing on Tuesday night trying to predict if I would feel better the next day. There were many cons to calling in. Mostly, the students would miss a day of new instruction. I had an emergency sub basket all ready with work for them, but it was just practice. Also, I would miss our class picture. In the end, the sickness won and it is good I did stay home. I ended up losing 5 pounds in one day to being sick. I was miserable. 

So my prime factorization lesson seemed rushed as I was trying to make up for a lost day. But I tried to vary the activities the students did, and gave them time to talk about the math. 

We started the lesson with reviewing what prime and composite numbers were. We talked about definitions, debate over which numbers were prime and composite and watched this video.

In one class, we had to talk in length about the difference between a multiple and a factor. 

Then we added a page to our notebook about prime factorization that looked like this. 

The tree flips down and there is another practice factor tree underneath. The students then got a practice sheet to work on with their group which we then checked. 

Afterwards, I gave everyone a dry erase marker and they practiced making factor trees on their desks while I went around checking and asking questions. 

Some common mistakes I saw were wanting to make the prime factorization smaller. Like taking 2x3x5 and wanting to collapse it to 6x5. We would go back to the definition of prime factorization and ask ourselves if all the numbers were prime. Also, some students just did the factor tree and thought they were done. I had to remind them that the factor tree was the process, not the actual prime factorization. 

Next, I will pull students in small groups and practice so I can really who has it and who needs more help. 

One station I will have next week while I pull students in small group is this Prime Factorization Match Up with QR codes. I try to have many of the stations that my students do include instant feedback. I am actually much better at grading this year than I have been in the past, but it is still not same day grading. Students need to know if they are doing it correctly. This way, they can check right away. Plus they'll have an ipad which they still think is cool.