bot with shopping

import math

print("Hi, I am Marvin, your personal bot.")
print("You can select one word of the menu, writing the word")
print("add   subtract   multiply   divide   volume   average   shopping")
command = input("How can I help? ")

if command == "add" or command == "plus":   # Adding code to add in lines 8-16
    print("lets add two numbers")
    input1 = input("Number 1> ")
    input2 = input("Number 2> ")
    number1 = float(input1)
    number2 = float(input2)
    result = number1 + number2
    output = str(result)
    print(input1 + " + " + input2 + " = " + output)

elif command == "subtract":   # Adding code to subtract in lines 18-26
    print("lets subtract two numbers")
    input1 = input("Number 1> ")
    input2 = input("Number 2> ")
    number1 = float(input1)
    number2 = float(input2)
    result = number1 - number2
    output = str(result)
    print(input1 + " - " + input2 + " = " + output)

elif command == "multiply" or command == "multiplication":   # Adding code to multiply in lines 28-36
    print("lets multiply two numbers")
    input1 = input("Number 1> ")
    input2 = input("Number 2> ")
    number1 = float(input1)
    number2 = float(input2)
    result = number1 * number2
    output = str(result)
    print(input1 + " * " + input2 + " = " + output)

elif command == "divide" or command == "division":   # Adding code to divide in lines 38-46
    print("lets divide two numbers")
    input1 = input("Number 1> ")
    input2 = input("Number 2> ")
    number1 = float(input1)
    number2 = float(input2)
    result = number1 / number2
    output = str(result)
    print(input1 + " / " + input2 + " = " + output)

elif command == "Volume" or command == "volume":   # Adding code to volume in lines 48-57
    print("lets calculate volume of cylinder with 2 values, ratio and high in cms.")
    input1 = input("ratio > ")
    input2 = input("high > ")
    ratio = float(input1)
    high = float(input2)
    #pi1 = 3.14
    result = math.pi * ratio * ratio * high
    output = str(result)
    print("volume of cylinder = " + output + " cms^3")

elif command == "average" or command == "Average":   # Adding code to average in lines 59-68
    print("lets calculate the average of some numbers!")
    how_many = input("How many numbers>")
    how_many = int(how_many)
    total = 0
    for number_count in range(how_many):
        number = input("Enter number " + str(number_count) + ">")
        total = total + int(number)
    result = total/ how_many
    print("the average = " + str(result))

elif command == "shopping" or command == "Shopping":   # Adding code to shopping in lines 70-84
    shopping = []
    how_many = input("how many items of shopping do you have? ")
    how_many = int(how_many)
    total = 0
    for item_number in range (how_many):
        item = input("What is the number " + str(item_number) + "? ")
        shopping.append(item)
        total = total + float(item)
    print(shopping)
    print("Total shopping = " + str(total))

    for item in shopping:
        print(item)
    print("You have " + str(len(shopping)) + " items in your shopping list" + " and the total shopping is = " + str(total))

else:
    print("sorry I dont understand")