例如，从阿拉伯数字系统中取出一个数字，比如说9。

For instance, take a number from the Arabic numeral system, such as 9.

youdao

现在把它映射回阿拉伯数字系统，毫无疑问，你会得到9。

Now map that back to the Arabic numeral system and you end up with, no surprise, 9.

youdao

阿拉伯数字0不能映射到罗马数字系统。

The Arabic numeral zero cannot map to the Roman numeral system.

youdao

阿拉伯数字0不能映射到罗马数字系统。

The Arabic numeral zero cannot map to the Roman numeral system.

youdao