You need to change this:
scanf(" %c", &operation);
I'm not sure what the 'h' was doing in there, but you definitely need a space before the %c
to eat up the newline after entering the first number.
Also, to print the answer you need to change this (and all similar lines):
printf("\n Answer = ", firstNumber + secondNumber);
to something like this
printf("\n Answer = %f", firstNumber + secondNumber);
(You forgot to put in the format specifier.)
Moreover, you really need to fix the spacing of your code!