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### Math Used Every Day

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Date: 11/20/2001 at 23:04:49
From: Swanniqua Puryear
Subject: What type of math do I use every day?

What type of math do I use every day?
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Date: 11/21/2001 at 06:15:49
From: Doctor Pete
Subject: Re: What type of math do I use every day?

Hi,

Thanks for writing to Dr. Math. That's an interesting question. I
don't know, really - what's your day like? I mean, typical people go
through their daily lives using various math concepts without even
knowing it, but then again, you're an individual, and different people
do different things.

For example, maybe you don't use clocks. (Okay, most people do, but
believe it or not, not everyone does!) Or maybe you've never driven a
car, or you're not much of a shopper. Perhaps you've never played
sports, or watched television.  Maybe you've never used the Internet.

But since you're able to e-mail us and ask us this question, I think
it's pretty unlikely that you've never done these things. How do these
activities use math? Well, it's really simple.

Clocks tell time, but only if you know how to interpret them, which
uses math. In particular, telling time uses addition and subtraction.
How much longer until school gets out? How long did I sleep last
night? When's my favorite TV show on? And if you know how to use it,
clocks involve what is called sexagesimal counting; that is, counting
by sixties. There are 60 seconds in a minute, 60 minutes in an hour.
So we think of 15 minutes as a quarter of an hour, for example.  That
uses fraction concepts.

We do a bit of math when we drive a car. We have an intuitive
understanding of speed, for example. 30 miles per hour is slow, you
might say, or 50 mph is too fast for barreling down local streets.
How long would it take to drive from Los Angeles to San Francisco?
It's about 370 miles. Or could you determine your average speed if you
drove from Seattle to Tacoma in 20 minutes?

Same thing with sports, whether it's running track or seeing how far
you can throw that football. How many yards is it to first down? How
would you keep score without using math?

Shopping involves lots of math. How much change would you get if you
paid for a \$25.99 sweater with two twenties? How would you calculate
sales tax, or a 30% discount? Tons of math there.

Then again, maybe you love to build things, so you decide to get into
furniture design. You'll use geometry like there's no tomorrow....
How long do I need to make that cut, or what size should that dovetail
joint be? How many square yards of fabric do you need to upholster
that couch? What angle do I need to cut the panel by, to make it fit?

everything involves math of some sort. The computer you use is a
machine to do binary arithmetic incredibly fast; the house you live in
was constructed by architects who had to specify its dimensions, and
engineers who had to to determine the loads the various parts could
withstand. You would be hard pressed to find something that didn't
relate to math in some way.

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