Archive | Math Facts

Invisible Misunderstandings: Square roots of 2 and 3

There are large chunks of mathematical knowledge that we often assume students have down. In fact, they often lack that knowledge. A good example is this: most students I work with have virtually no sense as to the value of the square root of 2 or the square root of 3. This post offers a […]

How to tell if a Number is Divisible by 8

How to tell if 8 divides into a number. There is a simple test for this. This post explains this.

(Divisibility) Practice Makes Perfect

Practice problems for reducing fractions. Use divisibility tricks to reduce fractions.

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

Multiplication Trick #5 — Multiply Two-Digit Numbers by 11

There’s a quick and easy trick for multiplying two-digit numbers by 11. Dazzle your friends, amaze your family, begin your career in show-biz … o.k., maybe not show-biz, but still this is a pretty cool trick. Check it out!

Multiplication Trick #3 — Multiply by 25 FAST!

Here’s a great way to help students get two for the price of one. First, they make connections between multiplication and a topic very dear to their hearts: money. That’s because the trick is for multiplying by 25, and in using this trick, you use the fact that four quarters make a dollar. Secondly, students […]

Multiplication Trick #2 — Multiply by 15 FAST!

Here’s a great trick that helps you quickly multiply by 15. It’s handy for many real life situations, such as when you need to calculate a 15% tip at a restaurant. It involves nothing more than simple math. Try it, and then watch as your friends and family gaze in amazement.