1. 十进位的
    A decimal system involves counting in units of ten.

    e.g. ...the decimal system of metric weights and measures...
           公制度量衡的十进制
    e.g. In 1971, the 1p and 2p decimal coins were introduced in Britain.
           英国于 1971 年开始使用十进制的 1 便士和 2 便士硬币。

2. 小数
    A decimal is a fraction that is written in the form of a dot followed by one or more numbers which represent tenths, hundredths, and so on: for example .5, .51, .517.

    e.g. ...simple math concepts, such as decimals and fractions.
           简单的数学概念，如小数和分数