Every year when we study the graphing of linear inequalities in two variables, I get frustrated with my student's lack of understanding of inequality symbols. Of all the misconceptions that students learn in elementary school math, the alligator is the worst. You know what I'm talkin' about right??? The students learn that the alligator always eats the bigger number in order to help them understand the concept of an inequality.

Unfortunately, many students are completely stumped when determining if an ordered pair is a solution to an inequality when they end up with a statement like 0 < -6. They think that since the inequality is opening up toward the -6 that -6 is the bigger number and they shade their graph in the wrong part. It takes a lot of work to undo the concept of the alligator. I usually start with the number line and we talk about solutions of inequalities in one variable. The students have learned the "steps" in middle school, but they have no concept of what they are doing. They learn tricks for knowing which way to shade their number line, like "always draw your arrow the direction the symbol is pointing". I understand that teachers are trying to use terms that the student will understand, but I think if you give them enough visual examples and not just the "steps" they will eventually understand the concept of less than, greater than, and equal to.

Sorry for the rant today, my Algebra class really are going great and I don't have a lot to complain about, but gosh I hate that alligator and I just needed to tell someone.

## 5 comments:

I completely agree with you. I absolutely hate the alligator and all other little "tricks" some teachers choose to teach instead of explaining to them and helping them understand the true concept. It's very frustrating for high school teachers!!!

omg, I am with you 100% on this! And I'm immersed in it now, fighting the good fight at my middle school to teach them MATH, not tricks. We really need to do more vertical talking with the HS and MS people together in our district. Not by subject... ALL of us.

I teach at a school with almost all international students - students from other countries have similar "alligator" heuristics to work with inequalities. It is really difficult, not only to undo the damage of the alligator, but to explain that it's not just a "language or culture thing" but an actual math inaccuracy in certain situations.

The alligator is the worst. Great post!

I haven't come across a reason to hate the alligator yet, but I hate the shading tricks that the lower grade teachers share with kids. They break down when the inequality is solved as 3<x. Although I want my students to put the variable on the left, sometimes they forget and if they rely on the "way the arrow points" they'll end up wrong! If we spent as much time teaching vocabulary as we do tricks, kids would know math much better, I think!

iisanumber.blogspot.com

I used this explanation in my senior Math for College Readiness class this year to see if they remembered it from past class. I haven't the boy in class that got his arm bit off by an alligator this past summer! Ifelt horrible when he said something about it, but he is extremely good natured about it and always makes us laugh! They broke me from ever even receding to it again!

Post a Comment