What is exponential notation in this problem? I think that it is A.BeK, where 1<=A<=9. Am I right?
What parts can be absent?
1)For example, are the numbers

1.0
1.e10
.1
5
9e1
possible in this problem?

2) Which output is correct?
7.000000000000000000
OR
7.000000000000000000e0

3) Which output is correct?
1.5e3
OR
1.500000000000000000e3