import os
import math
import fractions
 
if os.name == "nt":
    os.system("color 48")
    os.system("title Calculator")
    def clear():
        os.system("cls")
 
else:
 
    def clear():
        os.system("clear")
 
class Calc:
 
    def menu():
        clear()
        print ("Welcome to calculator!")
        print ("----------------------")
        print ("1) Exponents          ")
        print ("2) Division           ")
        print ("3) Multiplication     ")
        print ("4) Addition           ")
        print ("5) Subtraction        ")
        print ("6) Square Root        ")
        print ("7) Simplify Fractions ")
        print ("8) Factors            ")
        print ("9) Exit               ")
        print ("----------------------")
        menu = str(input("Choose one: "))
 
        if ( menu in list("123456789") ) == False:
            clear()
            print ("Please type a valid option!")
            input ()
            Calc.menu()
 
        methods[int(menu)-1]()
 
    def exp():
        clear()
        print ("? to the - power equals -")
        p1 = int(input())
        print ()
        print (p1, "to the ? power equals -")
        p2 = int(input ())
        print ()
        p3 = pow(p1, p2)
        print (p1, "to the", p2, "power equals", p3)
        input ()
        Calc.menu()
 
    def div():
        clear()
        print ("? divided by - equals -")
        d1 = int(input())
        print ()
        print (d1, "divided by ? equals -")
        d2 = int(input())
        print ()
        d3 = d1/d2
        if (d1 % d2) == 0:
            d3 = int(d3)
        print (d1, "divided by", d2, "equals", d3)
        input ()
        Calc.menu()
 
    def times():
        clear()
        print ("? multiplied by - equals -")
        m1 = int(input())
        print ()
        print (m1, "multiplied by ? equals -")
        m2 = int(input())
        print ()
        m3 = m1*m2
        print (m1, "multiplied by", m2, "equals", m3)
        input ()
        Calc.menu()
 
 
    def add():
        clear()
        print ("? plus - equals -")
        a1 = int(input())
        print ()
        print (a1, "plus ? equals -")
        a2 = int(input())
        print ()
        a3 = a1+a2
        print (a1, "plus", a2, "equals" ,a3)
        input ()
        Calc.menu()
 
    def minus():
        clear()
        print ("? minus - equals -")
        s1 = int(input())
        print ()
        print (s1, "minus ? equals -")
        s2 = int(input())
        print ()
        s3 = s1-s2
        print (s1, "minus", s2, "equals", s3)
        input ()
        Calc.menu()
 
 
    def square():
        clear()
        print ("The Square Root of ? is -")
        sqrt1 = int(input())
        sqrt2 = math.sqrt(sqrt1)
        if ( str(sqrt2).split(".")[1] ) == "0":
            sqrt2 = int(sqrt2)
 
 
        print ()
        print ("The Square Root of", sqrt1, "is", sqrt2)
        input ()
        Calc.menu()
 
    def frac():
        clear()
        print ("?/- simplified is -/-")
        fr1 = int(input())
        fr11 = str(fr1)
        print ()
        print (fr11 + "/- simplified is -/-")
        fr2 = int(input())
        fr22 = str(fr2)
        print ()
        fr3 = fractions.Fraction(fr1, fr2)
        fr33 = str(fr3)
        print (fr11 + "/" + fr22, "simplified is", fr33)
        input ()
        Calc.menu()
 
    def factors():
        clear()
        f = int(input("Type the number you would like to find the factors of: "))
        f2 = []
        for f1 in range(f + 1):
           if f1 != 0:
               if (f % f1) == 0:
                   f2.append(str(f1))
        print ("The factors of", f, "are", ",".join(f2))
        input ()
        Calc.menu()
 
methods = [
Calc.exp, 
Calc.div,
Calc.times,
Calc.add,
Calc.minus,
Calc.square,
Calc.frac,
Calc.factors
]
 
Calc.menu()

>>> a = eval('5+8886/45*4554545')
>>> a
899370824.3333334

import math
class Calculator(object):
    '''Doc_string info about class'''
    def calculate(self, expression):
        self.value = eval(expression)
 
    def square(self, sqrt1):
        '''This look like a function,but inside a class is called a method'''
        self.b = math.sqrt(sqrt1)
 
    def __str__(self):
        return self.value
        return self.b
 
#here a make the method of class short
#and i do user_input and printing outside of the class(you can of course make a menu but not in the class)
a = Calculator()
print('Calculate +-*/ and Square Root')
b = input('values')
a.calculate(b)
print('The sum of %s is %d' % (b, a.value))
 
c = int(input('Enter Square Root value'))
a.square(c)
print('The square Root of %d is %d' % (c, a.b))
 
''' my output-->
Calculate +-*/ and Square Root
The sum of 45+78*4545/56 is 6375
The square Root of 25 is 5
'''