Is a square a rhombus? When Everyday Math makes mistakes

Everyday math: please correct this serious mistake!

It's only week number three of the school year, and we are reviewing things we my older son should've learned in 3rd grade, here it's parallelograms.

In unit 1 study links (homework page) 1.4 question 2a. The question: Is a square a rhombus? My son brought home tees review sheets which lacked pictures of parallelograms and some further explanations. Using some of my mommy resources I pulled out a geometry book I had from my brothers recent High School SAT / ACT prep books, I tore out the relevant pictures and tapes them to the fridge, including some definitions of squares, rhombus and rectangles. These items may be in my sons fourth grade text book, however he hasn't been encouraged to bring his text book home.

Homework sheet, study links in Everyday math

Is a square a rhombus? When Everyday Math makes mistakes, a photo by areyousureaboutthatblog on Flickr.

(As an aside, this was a good opportunity to build our vocabulary on Polygons, and the names of other many sides shapes. We googled a list and mom hand drew a chart for the fridge. Part of "moms homework" my son needed to review these Polygons daily and into week two I was quizzing him on the names.)

Our homemade homework supplement, a picture guide to polygons

Is a square a rhombus? When Everyday Math makes mistakes, a photo by areyousureaboutthatblog on Flickr

The premise of this study link is a parallelogram is a quadrangle that has two pairs of parallels idea. TRUE! However there's a second factor not covered here, and that's a square has four-right angles as well (it's really a 2-part definition you can see in the geometry books definition).

Geometry book helper page

Is a square a rhombus? When Everyday Math makes mistakes, a photo by areyousureaboutthatblog on Flickr.

I realize the objective was to help students understand in this specific lesson that a square is a quadrangle (a 4 sided object) ... However the answer is not YES as the answer guide dictates.

The answer sheet

Is a square a rhombus? When Everyday Math makes mistakes, a photo by areyousureaboutthatblog on Flickr

Drawing certain conclusion based on similarities is fine, however generalizing is not. Or removing portions if definition isn't right either. The definition of a square, and a rhombus, was coincidentally on our fridge sheets. I encouraged my son to write the correct answer - No, and write our definition. The parent guide stated the opposite and I didn't eat to encourage him learning a wrong fact, for the sake if this one work sheet, to only relearn the information (hopefully) in a later grade.


Make mistakes, (fix them) breathe, reflect and Laugh.Out.Loud.