We want to review how to divide these numbers
written in scientific notation on the TI-84 graphing calculator.
And then we'll write the result in both
scientific notation
as well as decimal notation. So it's a pretty straightforward process,
as long as we know how to type scientific notation into the graphing calculator.
So for our numerator we have
four point two times ten to the fourth, so we'll type in four point two.
And then we want this key here that has two capitol E's in blue,
so we'll press second, comma. And now we just type in the exponent on ten,
so we'll type in four. So this is how we
represent four point two
times ten to the fourth on this graphing
calculator, and then we'll divide this by
eight point four times ten to the negative three.
So we type in eight point four, second,
comma, negative three. Be careful not to enter minus three,
where you will get an error. So our quotient is given here decimal notation,
so we have one, two, three, four,
five, six zeros. So we have
five followed by six zeros, or five million.
But now we also want to write this in scientific notation.
Remember in scientific notation
this number here has to be greater than, or equal to one,
and less than ten, so if we write five million without the commas it'll be helpful.
The decimal is right here,
but for scientific notation it would have to be here.
So we're going to have five times
ten raised to some power,  and the power is determined by how many places we move
the decimal.
So we moved it one, two,
three, four, five, six, and that's going to be a positive six.
The way remember this is that when you
multiply
something by ten to a positive power, this
number's going to get larger,
and we did start with a large number, so the exponent does have to be positive.
Let's go ahead and just try one more for
practice. So our numerator is six
times ten to the negative three, so we type in six,
second, comma, negative three. Then we'll divide this by
three times ten to the second, entered
as three,
second, comma, two. We don't want to use this
E in our notations, it's going to be two times ten to the negative five power.
And now we also want to convert this to decimal notation this time.
So if we use the number two where the
decimal point is here,
multiplying by ten to a negative power is going to make this number smaller,
so I know I have to move the decimal
point left
five places.
So one,
two, three, four, five. So we have to add four zeros here.
So in decimal notation we would have point
zero, zero, zero, zero, two.
And often you'll see a zero in the one's place value.
So this would be tenths, hundredths,
thousandths, ten thousandths,
hundred thousandths. This would be two hundred thousandths.
