Categories
Area Expressions & Equations

Area, Rectangles, Variables

chris shore (1280x850)

Chris Shore passes on the above, and he thinks that things just aren’t clicking for this kid. I’m inclined to agree. What would you all recommend? What’s the next step for this kid?

Categories
Numbers & Operations in Base 10 Rounding

Significant Figures

TheCommonMistake WhatsGoingOnHere

From the submitter: “I came across these answers to sig fig questions when marking a pre-algebra numeracy test last night. I’ve attached two answers, one is a very common mistake where students just can’t believe that they are asked to round up that much. The second… well I don’t have any idea what the student was thinking, so I thought your readers might be able to help.”

Readers?

Categories
Exponents Numbers & Operations in Base 10

Exponents Mistake from Middle School

cathy campbell

What makes this mistake so common?

Thanks to Cathy Campbell for the student work!

Categories
exponents Expressions & Equations Middle School

Exponents – Positive Integer Powers

Thoughts?

(via Chris Robinson)

Categories
Area Decimals Geometry Middle School Multiplication Perimeter and Volume

Area of Walls

What’s the mistake? How can you help the kid?

When you’re done with this post, go check out Mary Dooms’ blog and go follow her on twitter. Thanks for the submission, Mary!

Categories
Decimals The Number System

Repeating Decimals and Rounding

What’s going on here? What’s the misconception? What is there to build on?

Thanks to Nathan Kraft for the submission. Click on the blue words to check out his blog and this blue word to follow his tweets.

Categories
Converting Units Ratios & Proportional Relationships

Converting Units

What’s the misconception? But what does the student know? How would you bridge the gap?

Categories
6.RP.3 Rates

Rates

We here at the MathMistakes world headquarters got today’s mistake via email submission:

Question:  If you are driving 60 km/h, how far would you go in 20 minutes?
Student’s answer: 1200 km

Since we don’t have much to work with, in terms of diagnosing the students’ error,  let’s do two things in the comments today.  First, leave a note if you have about the specific question and student answer. Second, let’s use the comments as a place to discuss strategies for helping students form an intuition for rates.