New to Java

I study in a key university of Malaysia,
my lecturer in data structure told me that the float data type, in the max value -3.40282347E38
the character "E" means 200 zeros after the "."

but i doubt, the "E" should be 10 power 38, isn't it?

and my another question is why both Max value and min value have a +- sign in front of them?
like max value is -3.4E38, while Min Value is +- 1.40239846E-45