.. and now a third!
text = “# This is not a comment because it’s inside quotes.”

3.1. Using Python as a Calculator
=================================

Let’s try some simple Python commands. Start the interpreter and wait
for the primary prompt, “>”. (It shouldn’t take long.)

3.1.1. Numbers
————–

The interpreter acts as a simple calculator: you can type an
expression at it and it will write the value. Expression syntax is
straightforward: the operators “+”, “-“, “*” and “/” work just like in
most other languages (for example, Pascal or C); parentheses (“()”)
can be used for grouping.

But let’s not get too fancy here. We’re talking about a calculator, people! Let’s start with some basic arithmetic:

# This script is a basic calculator that performs simple arithmetic operations using the operators "+", "-", "*", and "/".
# It also demonstrates the use of parentheses for grouping.

# Addition
2 + 3 # Adds 2 and 3 together and returns the result 5

# Subtraction
10 - 4 # Subtracts 4 from 10 and returns the result 6

# Multiplication
8 * 9 # Multiplies 8 and 9 together and returns the result 72

# Division
12 / 6 # Divides 12 by 6 and returns the result 2.0 (note: in Python 3, division always returns a float)

See? Easy as pie! But what if you want to do something more complex, like finding the factorial of a number or calculating the square root of a negative value? Well, that’s where Python comes in handy: it has built-in functions for those operations and many others. Let’s see some examples:

# Import the math module to access built-in functions for mathematical operations
import math 

# Calculate the factorial of 5 using the math.factorial() function
math.factorial(5) # returns the value 120

# Attempt to calculate the square root of -9 using the math.sqrt() function
# This will result in an error as the function only accepts positive values
math.sqrt(-9) # returns a ValueError due to the argument being a negative value

Oops! Looks like we can’t calculate the square root of negative numbers using this function. But hey, that’s what makes Python so greatit lets us know when something goes wrong and gives us helpful error messages to guide us in the right direction.

Who needs a fancy calculator app when you can do all this (and more) using Python?