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### Multiplying a Number by Zero

```
Date: 09/14/2001 at 10:24:41
From: Almas
Subject: When zero multiply with number

When any number is multiplied by zero, why is the result zero?
```

```
Date: 09/14/2001 at 15:04:06
From: Doctor Ian
Subject: Re: When zero multiply with number

Hi Almas,

Try thinking of multiplication this way. When we multiply two numbers
- call them A and B - we'll take a yardstick of length A, and use it
to move B steps away from zero.  So 2 * 3 would look like this:

2   2   2
|---|---|---|   <-- 2 * 3
+-------------------------
0

Note that multiplication is commutative - that is, you can multiply
two numbers in either order:

2   2   3
|---|---|---|   <- 2 * 3
+-------------------------
0
|-----|-----|   <- 3 * 2
3     3

If I multiply something by 1, I just take the one step:

6
|-----------|   <- 6 * 1
+-------------------------
0

Now, what happens if I multiply something by zero?  I start at zero,
and jump... no times at all!  So I stay at zero, regardless of what
the other number is.

Does this make sense?

- Doctor Ian, The Math Forum
http://mathforum.org/dr.math/
```
Associated Topics:
Elementary Multiplication

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