The Intersection of Fraction Talks and Clothesline Math: Formative Assessment and the 5 Practices

By Jenna Laib

My sixth graders are weary of pre-assessments.

No matter how many times we discuss the goal of a pre-assessment–for me to learn more about their current strategies and understandings, so that I can design learning experiences that fit them better–all of them seem to want to impress me with perceived “perfection.” (As flattering as this is, they are missing the point.) Continue reading “The Intersection of Fraction Talks and Clothesline Math: Formative Assessment and the 5 Practices”

The IM 6–8 Math Curriculum Changed My Math Methods Experience

By Anna Polsgrove

When I first started the Math Methods course at University of California, Irvine, all of my ideas on how to learn math took a complete 180.

During the first two months, a million questions swirled in my head as I worked through problems with my classmates: We don’t just teach the algorithm anymore? What do you mean “use representations to build conceptual understanding”? What is an area diagram? What are all of the multiple strategies to solve a problem? How am I supposed to anticipate misconceptions when I have never taught the curriculum?, just to name a few. Continue reading “The IM 6–8 Math Curriculum Changed My Math Methods Experience”

On Similar Triangles

By Ashli Black

The fact that a line has a well-defined slope—that the ratio between the rise and run for any two points on the line is always the same—depends on similar triangles.
(p.12, 6–8 Progression on Expressions and Equations)

As students are building their understanding of dilation at the beginning of grade 8 in Unit 2 of the LearnZillion Illustrative Mathematics 6–8 Math curriculum, an activity asks students to dilate different quadrilaterals using a given center and dilation factor on a square grid. Here are the results of two of the dilations in that activity involving triangles: Continue reading “On Similar Triangles”

Sometimes the Real World Is Overrated: The Joy of Silly Applications

By Charles Larrieu Casias

One of the cool things about math is that it can provide powerful new ways of seeing the world. Just for fun, I want you to open up this lesson from the grade 8 student text. Take a quick skim. What do you notice? What do you wonder?

When writing this lesson, I was guided by a few key questions:

  1. To paraphrase Dan Meyer: If I want arithmetic with scientific notation to be the aspirin, then how do I create the headache?
  2. What are some weird, silly comparisons involving really large numbers?
  3. Here, towards the end of 8th grade, what should students be doing to transition towards the high school mathematical modeling cycle?

Continue reading “Sometimes the Real World Is Overrated: The Joy of Silly Applications”

Warm-up Routines With a Purpose

By Kristin Gray

As a teacher, curiosity around students’ mathematical thinking was the driving force behind the teaching and learning in my classroom. To better understand what they were thinking, I needed to not only have great, accessible problems but also create opportunities for students to openly share their ideas with others. It only makes sense that when I learned about routines that encouraged students to share the many ways they were thinking about math such as Number Talks, Notice and Wonder, and Which One Doesn’t Belong?, I was quick to go back to the classroom and try them with my students. It didn’t matter which unit we were in or lesson I had planned for that day, I plopped them in whenever and wherever I could because I was so curious to hear what students would say. Continue reading “Warm-up Routines With a Purpose”

Why is the graph of a linear function a straight line?

By William McCallum

In my last post I wrote about the following standard, and mentioned that I could write a whole blog post about the first comma.

8.F.A.3. Interpret the equation $y = mx + b$ as defining a linear function, whose graph is a straight line; give examples of functions that are not linear. For example, the function $A = s^2$ giving the area of a square as a function of its side length is not linear because its graph contains the points $(1,1)$, $(2,4)$ and $(3,9)$, which are not on a straight line.

Continue reading “Why is the graph of a linear function a straight line?”

Why We Don’t Cross Multiply

By Kate Nowak
(co-authored with Kristin Gray)

“Ultimately, the goal of this unit is to prepare students to make sense of situations involving equivalent ratios and solve problems flexibly and strategically, rather than to rely on a procedure (such as “set up a proportion and cross multiply”) without an understanding of the underlying mathematics.”
Illustrative Mathematics 6–8 Math, grade 6, unit 2, lesson 12

Continue reading “Why We Don’t Cross Multiply”

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