6' = 6 feet
I will assume that you mean " to the power of two ". A symbol for any n-power is to put the number (n) on the side, above the number. Like this: nn.
The symbol for number is #
e is the symbol of the number e
0 is a symbol for the absence of a number.
its like a number on top of a number. sort of like a fraction... the dots are numbers and the line is like the fraction bar.