CALCULATOR

def sum(a, b):
  return a + b
    
def sub(a, b):
  return a - b
    
def mul(a, b):
  return a * b
    
def div(a, b):
  return a / b
    
a = 10
b = 20
    
print("sum:", sum(a, b))
print("sub:", sub(a, b))
print("mul:", mul(a, b))
print("div:", div(a, b))