Thursday, July 19, 2012

Making Math Easier: Break It Down

I taught my young cousin my multiplication shortcut last night.

For example, what's an easy way to solve 12 X 11?

As a refresher, 12 and 11 are "factors", and the answer is the called the "product."


1. Ask yourself, what 2 or more numbers add up to the first factor and are easy to multiply?

In this example, I know 10+2=12, and that both 10 and 2 are easy numbers to multiply with any factor.


2. Multiply each number by the second factor.

In our example, multiply 10 and 2 by 11:

So...
10 X 11=110
2 X 11=22


3. Add the products

110+22=132

And there you have it!

The example above is an easy and gets the point across. I still use this trick when I need to multiply numbers and don't have a calculator (like when I'm flying a plane).

Math tricks are not for everyone, but if it works and helps a student overcome a hurdle, then use it. There's no harm in doing things differently.

-Dr. Dave

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