Wrong-Headed Lattice Multiplication Being Taught to Children

Sep 1, 2015 by

Lattice Multiplication

“Wrong-Headed Lattice Multiplication Being Taught to Children”
From Donna Garner 

9.1.15

 

I sent Nakonia Hayes, an experienced math teacher and author of Saxon Math Warrior, the following video produced by the Khan Academy on the subject of Lattice Multiplication. This is a method of teaching multiplication which is widely used in Common Core.  I asked Ms. Hayes for her reaction to this video and to the lattice multiplication method:

 

Here is the link to the video: https://www.khanacademy.org/math/arithmetic/multiplication-division/lattice_multiplication/v/lattice-multiplication

 

 

Comments from Nakonia Hayes:

 

Welcome to Everyday Math and GOMath!  I watched the Khan lattice multiplication video.  Khan has sold out as one of those teachers who knows math that he learned with traditional methods but thinks this kind of math is more “fun,” which too many teachers equate with “learning.” (He even used the word “fun” in his explanation.)

 

First, to understand this method, one needs to know his/her multiplication table and place value. At the fourth grade level, where this method is heavily used in GOMath!, many students do not know these basic facts. Sooo, that means they are having to look up the products of factors on a multiplication table and then having to insert the digits in the correct spaces after having drawn and labeled the lattice.

 

Second, if students have a directionality problem, which many do (i.e., being able to switch mentally from one direction to another and not get lost), this method will lose him/her just in the drawing of the lattice, let alone in putting digits in correct spaces.

 

Third, look how much more time it takes to work a problem with this method.

 

Fourth, until someone can show me a significant number of students who improved their “number sense” by working multiplication problems this way, compared to those who work the problems in the traditional way, I see no advantage to teaching a method that takes a lot of additional and limited learning time and energy. (I need to see a majority of such students from all subgroups passing algebra in the 8th grade and then enrolling in higher math and science courses in high school.)

 

To order Nakonia Hayes’ book, Saxon Math Warrior, please go to:  http://saxonmathwarrior.com/

 

 

Donna Garner

 

Wgarner1@hot.rr.com 

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