Commodore VIC-20 Programmer's Reference Manual page 72

Here are some examples:
Scientific Notation
2E1
10.5E + 4
66E + 2
66E-2
-66E-2
1E-10
94E20
Standard Notation
20
105000
6600
0.66
-0,66
0.0000000001
9400000000000000000000
As the last two examples show, scientific notation is a much more
convenient way of expressing very large or very small numbers.
VIC BASIC prints numbers ranging between 0.01 and 999,999,999
using standard notation; however, numbers outside of this range
are printed using scientific notation.
Consider the following out-of-range examples:
?.009
9E-03
READY.
?.01
.01
READY,
7999999998.9
999999999
READY.
7999999999.6
1E + 09
There is a limit to the magnitude of a number that the VIC can
handle, even in scientific notation. The range limits are:
Largest floating point number: -1.70141183E + 38
Smallest floating point number: ±2.93873588E-39
Any number of larger magnitude will give an overflow error. For
example:
71.70141184E+ 38
7OVERFLOW ERROR
READY.
Any number of a smaller magnitude will yield a zero result. For
example:
72.93873587E-39
0
56
I