Is it possible to change variable values over time?

Answer 1

Yes, it is. You can't change the value of constants however.

Answer 2

yes it is

Answer 3

yes

Answer 4

use var if you will change the value of the variable, use let when no need to change the value.

Answer 5

yes you can change the value unless it is constant

Answer 6

You simply type <name_of_variable> = <new_value>, without preceding name by "var".