So i want to have a user input a number using 

```
input = raw_input ("What is your number")

```

and then this number lets say 5 has the following operations completed

```
result = input + 3 then * 2 then - 4 then - (2 * input) then + 3

```

so with my example of 5 the following would be the chain of maths

```
5 : 8 : 16 : 12 : 2 : 5

```

and finally a print statement of

```
print "Your answer is: " + result

```

I am doing this all in terminal on my mac and using nano as a text editor, I have tried multiple ways such as assigning every single number to a variable later and then only using letters and of course the obvious way of just plugging the numbers in but I always get an error.

Here is one of the sections of code I have tried

```
    #!usr/bin/env

a = 6
b = 3
c = 2
d = 4

sum = ((((a + b) * c) - d)( - ( c * a )) + b)

print sum

```

then saving the file as a .py file and the whole chmod +x filename.py then python filename.py and always an error, for the example above i get

```
TypeError: 'int' object is not callable

```