How to quickly multiply by 25. This is a fun math trick that anyone can learn in 5 minutes or less.

# Archive | Mental Math

# Tutor Tales — Algebra/Arithmetic Connections

A cool way to help students learn from mistakes they make in algebra.

# “Fraction Sandwich” Practice Problems: Dividing a Fraction by a Fraction (without choking!)

Last week I sent out a blog that helps students divide a fraction by a fraction. The technique is called the “Fraction Sandwich.” To help students “get the hang” of this technique, here are 10 practice problems for dividing one fraction by another.

# 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 […]

# Fraction divided by a fraction

Is there any way to make it easier to divide one fraction by another fraction? Read the post and you’ll see that it is possible. Here is a great math trick that makes it easier to divide fractions. Read the post and then try the division trick. You’ll be glad that you did.

# ANSWER: October Problem of the Month

Answer to October’s Problem of the Month, a problem about divisibility by 9.

# Memorizing those Times Tables

Yes, there IS a way to help students master the times tables of multiplication facts. This article tells you how you can do it in a fun and playful way.

# Find the GCF — QUICKLY!

Here’s a handy-dandy tip that makes it easier to find the GCF. It gives you an upper limit for the GCF, so you know when you can stop testing numbers and tell the world that you’ve found the GCF.

# Multiplication Trick #4: Multiplying Teen Numbers

Believe it or not, THERE IS a quick way to multiply two numbers together when both numbers are “teen” numbers. In other words, you can do a problem like 14 x 18 fast and just in your head. Here’s how ….