Reflection: Joy How Does a Parabola Grow? - Section 2: Getting Started: Identifying the Features of a Graph


At the end of the narrative for this section, I noted that the most common errors I'll see students make are missing negative signs or mixing up the order of x and y in a coordinate pair.  

These are the kinds of details that many students overlook when they're so focused on understanding the vocabulary or parsing broader concepts, and when these errors happen I am usually compelled to provide feedback in contradictory ways.  On the one hand, I want to tell students: "You're getting the idea, and that's what's most important, don't let those big red x's get you down -- you're just a few details away from really getting this," while on the other hand, I have to show students that "right is right."  

I frame it as a test-prep thing.  I tell students to think about a multiple choice test.  Let's say that you're asked to give the roots of a quadratic function on a test.  You know what you're doing when you factor or look at a graph, but at the last moment, you leave off a negative sign.  It's a pretty sure bet that the makers of the test are going to be ready for you, providing both the positive and negative value of the answer you're looking for.  Even if you know everything about factoring, the simple fact is that if you mix up the signs, you're just as wrong as a student who has no idea what they're talking about.  Is that fair?  Of course not!  But it's what you're up against.

When I tell this tale to kids, they get it.  They know they've seen this before.  And we all get fired up.  It's us versus that bedeviled test - and we're not going to let "them" get us down!  Delta Math, being the computer program that it is, gives us the same opportunity: the machine doesn't care how much you know, it just cares if you get the right answer, so you better pay attention to those signs, or the robots will win!

I've applied the "Joy" tag to this reflection because I've found that this approach helps to create a positive vibe in the classroom.  When we turn exams from inevitable evils into nasty dragons that we can't wait to slay, and when students recognize that I am completely on their team in helping them achieve that goal, we can roll up our sleeves, grab our swords, and of course, pay close attention to which way is up.

  It's Us vs. THE TEST!
  Joy: It's Us vs. THE TEST!
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How Does a Parabola Grow?

Unit 10: Quadratic Functions
Lesson 11 of 21

Objective: SWBAT identify the key features of a parabola, and to use the structure of the perfect squares to see a novel shortcut for plotting successive points on the graph.

Big Idea: It's not so much about the shortcut as it is about the structure it reveals!

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Math, Graphing (Algebra), Quadratic Equations, graphing functions, delta math, novel strategies, Growth Mindset, Algebra 1
  43 minutes
heres a shortut reized
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