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 […]

# Archive | Number Sense

# The GCF (aka GCF) … what is it?

The GCF is the greatest common factor, and it’s a key concept in math. This term is also known as the GCD, the greatest common divisor. Students often need to find this quantity either for a pair of numbers or for three or more numbers. For example, knowing the greatest common factor allows students to reduce […]

# Front Page News (in the “Mathematical Tribune”)

They’ve done it! Mathematicians, using a network of interconnected computers, have discovered a new largest-ever-found prime number. Click here to “read all about it.”

# Journey to the LCM … and Beyond!

In this blog/video I want to take you a little bit deeper into the world of … the LCM! Yes, that fascinating little mathematical entity is beckoning us to explore it further. Several readers wrote to me after I posted my LCM “trick,” saying they want to see me demonstrate WHY this “shortcut” works. One […]

# Divisibility by 2, 5, 10

In hopes of helping students feel more comfortable with numbers, I’ve decided to post some videos about divisibility. Here is the first of these videos, on the divisibility rules for 2, 5, and 10.

# Temperature for Positive and Negative Numbers

Kids struggle with positive and negative numbers … that’s a given. But I’ve recently hit on a reliable way to eliminate the confusion … temperature. Using a temperature scale as a model for solving integer problems has several advantages: 1) It’s a system students already know from everyday life. 2) The relationships among positive temperatures, […]

# Find the LCM – FAST!

Here’s a short video on how to find the LCM. It uses a trick that I have not seen anywhere else, and the approach is quite fast. The information in this video dovetails with the info in this post. I hope that you find this video helpful.

# How to find the LCM — Intuitive Method

Recently I’ve been interested in discovering a cool, new way to get the LCM for a pair of numbers. Criteria: Method that is short and sweet. Even more important, a method that makes sense INTUITIVELY. I can’t speak for any of you , but I’ve always felt that the standard techniques for finding the LCM […]

# Find the LCM (aka LCD) in Two Easy Steps

This is really the “Week of the LCM” for me. Just as I was finishing my last post, on a new way to find the LCM for a pair of numbers, I discovered another way to do the same thing. I was looking at the problems at the end of my last post, these problems: […]

# Quick Easy Way to Untangle Confusion re: “Greater” and “Less”

Once students learn about negative numbers and absolute value, the concept of greater and less becomes a bit “cloudy.” What was once clear is now “muddied.” But there is an easy way for students to tell which of two numbers is greater and which is less. That method involves looking at the numbers on the […]