By William McCallum

“I’m afraid I can’t explain myself, sir.
Because I am not myself, you see?” Alice in Wonderland.

The idea of equivalence in mathematics is tricky for learners, because when we talk about two things being equivalent, for example the fractions $\frac35$ and $\frac6{10}$, we are emphasizing two contradictory things: Continue reading “Fractions: Units and Equivalence”

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”

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”

By Charles Larrieu Casias

The number line is an anchor representation that threads through the entire middle school curriculum. For this blog post, I want to focus on a creative use of the number line in grade 8 to explore scientific notation and irrational numbers. Let’s zoom into a lesson. Continue reading “Fun With Zooming Number Lines in Grade 8”

By William McCallum

In everyday language, $\frac{a}{b}$, $a\div b$, and $a : b$ are all different manifestations of a single fused notion. Here, for example are the mathematical definitions of fraction, quotient, and ratio from Merriam-Webster online: Continue reading “Untangling fractions, ratios, and quotients”

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”

It was great to see so many of you at NCSM and NCTM. If we missed you, or you weren’t able to attend, read our NCSM and NCTM round-up below.

We enjoyed the conversations we had with those of you that are using the IM 6–8 Math curriculum and are looking forward to High School and Elementary.

Check out some photos and all of the IM presentations below, including Bill McCallum’s The Promise of Open Curriculum.

Which presentations did you attend and which was your favorite? Continue reading “NCSM and NCTM 2018 Roundup”

By Kate Nowak

This task is the first part of the culminating lesson of unit 2 in grade 8, which is about dilations and similarity. (You will need to create a free teacher account to open the link.) It is a variation on the popular “use shadows and similar triangles to determine the height of a tall thing that it is impossible to measure directly.”