Next, go to the bottom of the list, where you will find a box with a five-digitnumber in colour.
接下来，进入底部的名单，你会发现一个方框，一个五位号码颜色。
2
For example, a postal code in the United States is a five-digitnumber, optionally followed by a dash and a four-digit number. Listing 1 shows the regular expression that describes that format.
例如，在美国邮政编码是一个五位数，后面还可能跟有一个破折号加一个四位数。
3
Your children may not be looking for a number, especially if they’re young and have no context for five- or six-digit figures.