ex21.py

#!/usr/bin/env python3

def add(a, b):
    print(f"ADDING {a} + {b}")
    return a + b

def subtract(a, b):
    print(f"SUBTRACTING {a} - {b}")
    return a - b

def multiply(a, b):
    print(f"MULTIPLYING {a} * {b}")
    return a * b

def divide(a,b):
    print(f"DIVIDING {a} / {b}")
    return a / b

print("Let's do some math with just functions!")

age = add(30, 5)
height = subtract(78, 4)
weight = multiply(90, 2)
iq = divide(100, 2)

print(f"Age: {age}, Height: {height}, Weight: {weight}, IQ: {iq}")

# A puzzle for the extra credit, type it in anyway
print("Here is a puzzle.")

what = add(age, subtract(height, multiply(weight, divide(iq, 2))))
# iq = 100/2 = 50
# divide(50, 2) = 25
# multiply(180, 25) = 4500
# subtract(74, 4500) = -4426
# add(35, -4426) = -4391

print("That becomes: ", what, "Can you do it by hand?")