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### What Do Input and Output Mean in Math?

```Date: 04/09/2007 at 18:00:57
From: Bailee
Subject: input and output?

What is the relationship between the input and output on a table?  I'm
not quite sure what an input or output is.

input - the act or process of putting in.
output - production of a certain amount.

```

```

Date: 04/10/2007 at 09:23:06
From: Doctor Ian
Subject: Re: input and output?

Hi Bailee,

Think of it this way.  Suppose you go to the library, and you have the
name of a book, and the name of the author.  You hand that to the
librarian, and she finds the book and gives it to you.

In this case, the "inputs" are the name of the book and the name of
the author, and the "output" is the book.

Does that make sense?

In math, we can make up an expression, like

25 + 3*n

and we can choose a value that we want to assign to the symbol.  That
value is the "input".  So we can say, let's make n equal to 4.  The
input is 4, and the output is the value of the expression, when 4 is
substituted for the symbol:

4  ->  25 + 3*4 = 25 + 12 = 37

So the input is 4, and the output is 37.  We can pick a different
input, like 10:

10  ->  25 + 3*10 = 25 + 30 = 55

Now the input is 10, and the output is 55.  We can keep track of these
in a table,

input     output
-----     ------
4         37
10         55

So "input" roughly means:  a value that we choose.  And "output"
roughly means:  something that depends on the input.

Does that help?

- Doctor Ian, The Math Forum
http://mathforum.org/dr.math/

```

```

Date: 04/10/2007 at 19:52:07
From: Bailee
Subject: Thank you (input and output?)

Thank you so much that makes sense now!  And it helped me ace my test too!
```
Associated Topics:
Middle School Algebra
Middle School Definitions

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