Calculator that is part of a multipurpose program
I would suggest using a dict as switch-statement like structure. 

First some global helper functions/data structures:

math_dict_binary = {'+': lambda a, b: a+b,
                    '-': lambda a, b: a-b,
                    # fill out the rest of you binary functions
                   }
math_dict_uniary = {'sqrt': math.sqrt,
                    # rest of you uniary
                   }


def get_input(str_prompt):
    input = int(input("       * {}:  ".format(str_prompt)))
    blank()
    return input


in your main body:

elif userIn == ("math"):
    op = str(input("    * Enter operation (+, -, *, /, exp, sqrt, log): "))
    blank()
    if op in math_dict_binary:
        input_1 = get_input("Enter first number")
        input_2 = get_input("Enter second number")
        print( "    " + str(math_dict_binary[op](input_1, input_2)))
    elif op in math_dict_uniary:
        input_1 = get_input("Enter number")
        print( "    " + str(math_dict_uniary[op](input_1)))
    else:
        print("Not a vlaid math option")
        # deal with it