Categories
Geometry Graphing

Plotting Points

andy1 andy2

 

Thanks to Andy Zsiga for the submissions. He’s wondering whether anyone has perspective on why students would graph several points correctly, and then mess up the point that contains a zero as one of its coordinates.

Anyone have a theory?

Categories
Distributive Property Fractions Number & Operations -- Fractions

The Distributive Property of Fractions

See the title of the post.

What is the significance of this mistake? Say something smart about this piece of student work in the comments.

Categories
Fractions Number & Operations -- Fractions

Division by 1/4

Above are three different answers to 4 divided by 1/4. What understanding stands behind each of those wrong answers? How do you teach division by fractions?

Categories
Doesn't really fit anywhere Numbers & Operations in Base 10

Division by Zero

5 divided by 0 is 0.

Thoughts?

Related: http://rationalexpressions.blogspot.com/2012/11/how-not-to-teach-it-division-by-zero.html

Categories
Fractions Number & Operations -- Fractions

Classic Mistakes: Adding Fractions

I arbitrarily designate some mistakes to be “classics,” and this here is one of them.

No need to identify the mistake. It’s right there. But let’s get some wisdom in the comments. What is the significance of this mistake? Does knowing that this mistake is common change the way that you do (or should) teach?

[I didn’t exactly know how to tag this post, but it’s from a 9th grade classroom. For CCSS I tagged 5th grade.]

Categories
Doesn't really fit anywhere Number & Operations -- Fractions

Whole numbers and 1

This one is really interesting. We’ve got both a sample of student work, and on the left the student has crossed out \frac{5}{1}. We also have a record of the following student question:

Kid: [Raises hand.]

Teacher: “What’s up?”

Kid: “Are you looking for a 1 or, like, the number 1?”

What is the student’s question, and what does it reflect about what he knows and thinks? How would you help?

[The submission also comes with an answer, yielded by the teacher through further questioning, revealed in the comments.]

 

Categories
5.NBT.3 Decimals

From Khan Academy: Comparing Decimals

No, Sal Khan did not actually submit this question. But Andyhav3 asks:

What’s this student getting at with “the right side of the decimal,” and how might you help Andyhav3?

 

[Click here to see how your approach compares to how his question was actually handled.]