【Python】Learn Python the hard way, ex21 函数返回值return

def add(a, b):    print "ADDING %d + %d" % (a, b)    return a + b    def subtract(a, b):    print "SUBTRACTING %d - %d" % (a, b)    return a - b    def multiply(a, b):    print "MULTIPLYING %d * %d" % (a, b)    return a * b    def divide(a, b):    print "DIVIDING %d / %d" % (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 "Age: %d, Height: %d, Weight: %d, IQ: %d" % (age, height, weight, 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))))print "That becomes: ", what, "Can you do it by hand?"'''Test Result:Let's do some math with just functions!ADDING 30 + 5SUBTRACTING 78 - 4MULTIPLYING 90 * 2DIVIDING 100 / 2Age: 35, Height: 74, Weight: 180, IQ: 50Here is a puzzle.DIVIDING 50 / 2MULTIPLYING 180 * 25SUBTRACTING 74 - 4500ADDING 35 + -4426That becomes:  -4391 Can you do it by hand?'''