Tuesday, March 3, 2015

Seeking Converts: Divide Polynomials Using the Box!

Calling all who are weary from long division of polynomials, students forgetting all the caveats of synthetic division, and/or people looking for another method of division.

First of all, I love the box. I use it to multiply (I ban the word "foil" in my room) and factor, I briefly talk about it with completing the square - so why not division. I first saw the possibility on this post. I about lost my mind with excitement. Last semester I tried it for the first time and loved it.

Dividing by a linear factor? Use the box
Dividing by a linear factor w/ a coefficient other than 1? Use the box
Dividing by a quadratic/cubic/anything?? Use the box!

It always works. No tricks to remember. No extra steps. No extra multiplying/dividing. No times when you have to do something different.

The easiest way to understand is to look at the link above. I've also included the video of me explaining it to my students for their notes. I've also linked to the guided notes they take.

Students have also had great success with this and have found it easy. They've even taught their friends in other classes how to use this method =). Success!








Enjoy! Spread the word! 

PDF of notes

Unit 2: Quadratics

These are my notebook pages for my second unit of Math III (kind of like Algebra 2) on Quadratic Equations.

One thing I've started doing for this class is printing a detailed schedule on the back of our table of contents. Of course it is subject to change, but my honors students seem to really appreciate it and it helps me keep all the details of the bigger picture in mind as I go.



The first thing we talk about are operations on complex numbers. Left hand page are some notes I wrote and the right is a maze found here as a free printable from teachers pay teachers. 




The next topic is completing the square. I have them do a geometric investigation first. I got the idea from this site . It ends up that they need to cut the middle piece (ie b) in half. Looking at it now I only see one set of the squares, not sure where I got the three. I will try to scan my copy in. I have them color each row a different color so they can tell the difference between the 3 squares when doing the investigation.

The they go through Kate Nowak's completing the square algebraically. Early finishers continue to work on using the box to understand completing the square. Next time I will probably include Julie's investigation using the box here.

After we've done the investigation we come together and summarize in some notes I made. Available at bottom of post.






We spend another day practicing completing the square.

We then complete the square to find the quadratic formula and move into that.




The right hand page is a cut and paste matching activity I've had for a while from Teachers Pay Teachers.

Next up is factoring. At this point this is their third exposure to factoring. We spend one day on trinomials and four terms, one day on binomials.







Then we move into graphs. This is their 3rd time talking about quadratics, so I focus on changing mathematically between different forms. I have a graphic organizer on the different forms on the left. I copied some of the tables from this website to make the page on the left. Behind the table is the pre-assessment for the MAP shell project on the right.

On the right we used the MAP Shell project "Forming Quadratics". I modified it so they cut and pasted the graphs together rather than doing them as dominoes. Then they pasted it in the book and identified important parts of the quadratic (vertex, zeros, intercepts, etc.). You need to print one copy F/B and then a one-sided copy to make the booklet.





Finally, we talk about parabolas geometrically by discovering how to make a parabola from the focus and directrix. I stole this idea directly from Sarah Hagan at mathequalslove. I had technology issues that day, thus the completely ugly hack of her notes because I couldn't access box to download. Hopefully I will edit and type up mine at some point.





So that's my unit 2 in the notebook. I'm going to do a separate post on the activities I used for practice in class.

Link to all my documents for the unit (and some others from my Math II Quadratics - simplifying the quadratic formula, perfect square trinomials, etc.)