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### Mental Math

```Date: 07/25/2003 at 13:35:27
From: Charlie
Subject: Mental Math

I would like to find a trick for multiplying by 3367.

3367*27
3367*33
3367*32
3367*18
3367*17
3367*14
3367*15
```

```
Date: 07/31/2003 at 09:42:23
From: Doctor Stephanie
Subject: Re: Mental Math

Hi Charlie,

When I have seen these problems on tests that are specially designed
for mental math, I have tried to find similarities or trends from
other problems like them. You really are on the right track. When I
have seen a problem that has multiplied 3367 by another number, I
have noticed that almost always the other number is a multiple of 3.
When you multply 3367 by three you then find a number that is very
common in the "mental math world," 10101.

An example of how to use this would be to not view 3367 as 3367, but
as 10101 * (1/3).

Here is an example of how you might be able to use this to your

3367 X 15 =

10101 X (1/3) X 15 =

10101 X 5 =

50505

Keep in mind that this trick is only useful if the other number is
divisible by 3.

I hope this perspective has helped you find another way to approach
the problem or even find an even better "trick". If you have any more
questions or if this is unclear, feel free to write back!

- Doctor Stephanie, The Math Forum
http://mathforum.org/dr.math/
```
Associated Topics:
Elementary Large Numbers
Elementary Multiplication
Elementary Number Sense/About Numbers
Middle School Factoring Numbers
Middle School Number Sense/About Numbers

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