Since we'll be working with very large and very small numbers, we'll be using scientific notation to cut down on all of the zeroes we need to write. As a quick review:
and
which you'll see sometimes written as
even though
this is not proper scientific notation. For small numbers we have:
and
The last example shows that you subtract exponents when you divide numbers. If
the number had been 
,
you'd have
You add exponents if you multiply numbers. You subtract one from the
exponent for every space you move the decimal to the right. You
add one to the exponent for every space you move the decimal to the
left.
Most scientific calculators work with scientific notation. Your calculator will
have either an ``EE'' key or an ``EXP'' key. That is for entering scientific
notation. To enter 253 (
),
you would punch 2 
. 5
3
EE or EXP
2. To enter
,
you would punch
3 .
9
5
EE or EXP
3
[
key]. Note that
if the calculator displays ``3.53 -14'' it means
NOT
! Also if
you have the number 
and you enter 4
x 10
EE or EXP
3, the calculator
will interpret that as 
or ten times the number you really want!
last updated 29 Aug 95
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Astronomy
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