# GCF of 2 Numbers, Trick Finds it Fast

Ever need to find the GCF of two numbers? Here’s a trick for finding the GCF of any two numbers — very quickly. This is an original trick, so I doubt you’ll find it anywhere else online. But most important, it’s easy to use, and it works no matter how large the numbers might be. Also nice … learning this […]

# Helping Students REMEMBER the Difference in ‘LOOK’ Between Positive and Negative Slope

Some ideas just slap you in the face. I got slapped this morning as I was flying home from LA to Albuquerque. Those little cocktail napkins they hand out with “beverage service” often give me the urge to write. So this morning, nerdily enough, as I sipped my orange juice at 30,000 feet above the […]

# Origins of the Coordinate Plane

One of the legends of math relates to the invention of the coordinate plane system. The legend states that Descartes was inspired to invent this system after watching a fly move around on the ceiling over his bed. This post tells the story and points out its relevance for modern math teachers.

# Not all variables are created equal

Variables do not all serve the same purpose. Making this clear helps students more deeply understand algebraic equations, such as the equation for a line. This post shows how to understand the two kinds of variables in the slope-intercept form of a linear equation.

# Common Algebra Mistake: Interpreting Negative Signs in Front of Parentheses

Tricky area of algebra: negative signs in front of parentheses. This explains how we can help students relate the concept to everyday life, and thereby grasp it so they remember it!

# How to Survive College Algebra

You can survive College Algebra if you have the right tools. One of the best tools is my Algebra Survival Guide, which has helped more than 100,000 people succeed at this difficult subject. The Algebra Survival Workbook helps by providing additional practice problems. Check them out at Amazon.com