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.”

# Archive | Number Sense

# 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 number line and using a memory trick derived from the spelling of the words “greater” and “less.” Enjoy!

# Secrets of the Calculator, Part 1

Calculators can be great assistants when doing math. Unfortunately many students are unaware of the capability of many calculator keys. This is the first in an occasional series of posts that will help students learn how to make better use of the calculator.

# How to decrease Algebraic mistakes – Part 4

The double-slash notation comes to the rescue in algebra once again. In this post we learn how this clever notation device helps students combine positive and negative numbers, the trickiest pre-algebra concept of all. Read to find out how you can use this notation to make this concept easier for your students or children.