函数返回一个奇怪的值

Question

我之前使用Python制作了这个简单的转换函数，但现在当我查看它时，我只是注意到它的返回方式：100 * 8.8 = 880.0000000000001。它在使用10，1000等任何其他值时都有效。有人可以向我解释一下吗？

def converting_currency(usd):
    currency = input("What currency do you have? ('KR' or 'EU')")
    if currency == 'KR':
        amount = usd * 8.8
        print("If you have", + usd, "dollars, you have", + amount, "kronor")

    elif currency == 'EU':
        amount = usd * 10.5
        print("If you have", + usd, "euros, you have", + amount, "kronor")
converting_currency(100)

它返回：

What currency do you have? ('KR' or 'EU')KR
If you have 100 dollars, you have 880.0000000000001 kronor

Process finished with exit code 0