WEBVTT

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Now we're going to look at an example
problem using our calculator.

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This is the TI thirty X two S, 
and this is the model I recommend.

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Other calculators will do the exact same functions,
but things happen in a little bit different order.

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And where the buttons are and what
they call them are a little bit different.

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So if you're not sure how to use your
calculator, play around with it.

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And if you still need help, then please
feel free to come see me.

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We're going to solve this problem, and we're 
using numbers that are in scientific notation.

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And I want to show you how to enter
this correctly into your calculator.

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So my problem is six point one times ten to the fifth, 
divided by one point two times ten to the minus third.

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So I have two issues I have to worry about: 
one, how do I enter this number (the 6.1 x 10^5)

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in scientific notation into my calculator, 
and how do I enter the denominator correctly

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so that the right calculation is done. 
So, we're going to turn our calculator on.

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And I'm going to type 6.1, and then 
I have the times 10 to the fifth.

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The way we do this on the 
calculator is we use this EE function.

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So if I look here at this button that has 
x to the -1, above it in purple it says EE

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and that means scientific 
notation--the exponent.

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So I'm going to hit 2nd because I wanted 
to use the purple function there.

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I press EE, so it shows an E on my screen.
And then I put a 5 in.

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Now note, I did not put a multiplication sign in, 
I did not type 10, I just put 6.1 E to the fifth.

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And that means exactly the same as this: 
6.1 times 10 to the fifth.

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Now I'm going to divide, then I'm 
going to put in my denominator: 1.2.

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Again, I'm going to use my EE function, 
so I do 2nd, EE.

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And this time my exponent is to the negative 
three, so I use my minus sign here,

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this is the negative sign--excuse me, the negative
sign, not the subtraction sign--minus three.

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And when I hit equals, that will show me my answer. 
And it's showing it here in scientific notation.

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So, I have 5.1--because I'm going to round it to 
one decimal place--5.1 times ten to the eighth.

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So, we're going to write that down.

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Now, sometimes your calculator won't
be showing it in scientific notation,

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or you want to get something 
out of scientific notation.

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And what you do is you
use the 2nd button again.

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And here where it has DRG which stands for degree, 
above it you see SCI/ENG, so "scientific/engineering."

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So, I hit 2nd and scientific/engineering, and I want 
to make sure SCI--that will put it in scientific mode.

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If I want to just see the number NOT in scientific 
notation, I choose FLO for "Flo" [floating decimal]

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and that will show me the
number NOT in scientific notation.

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So here you don't see the times ten to the eighth, 
you see the whole number written out.

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And I can go back to scientific notation, 
and now again it shows it in scientific notation.

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So, that's the correct way to do the problem.
What I want to show you is how you DON'T

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want to do this, because I want you to see 
that there is a difference in the answer.

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So, here we've used the EE function,
our scientific notation, to show these values.

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Let's look at what happens if instead of using
the EE button, I use "times ten to the fifth."

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Now for the numerator it 
doesn't make a big deal.

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However, we're going to run into a
problem with our denominator.

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I'm going to hit divide, one point two, 
times ten to the minus third.

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Now, when I hit the equals sign, 
I get my answer, it's in scientific notation.

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But, note it's five point one times ten to the second,
a very different answer than what I saw before.

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And the reason for that is because what 
really happened is the calculator took

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6.1 x 10^5 divided by 1.2 
and multiplied by 10^-3.

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And that's not what we wanted to happen,

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so you need to make sure you use scientific 
notation so that you get the correct answer.