Radio Shack TRS-80 User Manual page 25

Chapter
4
Are There
More
Stars
or Grains of Sand?
In this
mathematical world
we
are
blessed
with very
large
and
very small
numbers.
Millions
of these
and
billionths
of those.
To
cope with
all
this,
your Computer
uses
"exponential
notation", or "standard scientific
notation"
when
the
number
sizes start
to get
out of hand.
The number
5 million (5,000,000), for
example, can be written
"5E+06".
This
means, "the
number
5
followed
by
six
zeros."
If
an answer
comes out "5E-06",
that
means
we must
shift
the decimal
point,
which
is
after
the
5, six
places to the
left,
inserting zeroes as
necessary. Technically,
it
means
5
X
10~ 6
,
or 5 millionths, (.000,005).
It's
really
pretty simple
once you
get
the hang
of
it,
and a lot easier to
keep track of
numbers without
losing
the decimal
point.
Since the
Computer
insists
on using
it
with very large
and very small
numbers,
we
can
just as
well
get in
the
good
habit, too.
Type
NEW
before performing the following
exercises.
1
EXERCISE
4-1
:
If
one
million cars
drove ten
thousand
miles
in
a certain year,
how many
miles did
they drive altogether that year? Write
and run
a simple
program which
will
give the
answer.
EXERCISE
4-2: Changes
lines
20 and 30
in
the
Car
Miles Solution
program (from Exercise
4-1) to express the
numbers
written there in
exponential notation, or
SSN
(Standard
Scien-
tific
Notation).
Then
RUN
it.
"3, 714,
983,
217,
-OR
WAS
THAT-"
Qrtechrncaliy^J^JG
6
,
which
is
&tjane$ten to
the
:
sixth
pbwei:
'
'f§':'::-/
5*10*10*10*10*10*10
Now
ypu
$t&
'.see
the value of
scientific
notation!
in
our
&A&C,
that's 5/19/10/10/10/10/10
Didn't
forget the
02013
did
you?
Up
till
now
we've
been reminding
you
thstyoi* ha*e toenter
eaefe
Ime
or
command
—
but
from
now
oil,
well
assume
you've got that
Utile
routine
ifiatte*
<toW
23