Use the algorithm that generates a Random SSN with a valid source area number (first 3 digits).

使用生成包含有效原区号的随机SSN(前3位数字)的算法。

youdao

Because it is an area of outstanding natural beauty, the number of boats available for hire on the river is limited.

这是一个自然风景极美的地方，所以河上可供租用的船只数量有限。

《柯林斯英汉双解大词典》

The fourth to the seventh digits tell you which area the number is recorded in.

第4到7位数字告诉你数字被记录在哪个区域。

youdao

Experts say this park has the greatest number of arches of any similar geographic area in the world.

VOA: special.2009.04.15

But the Global Heritage Fund says increasing the number of visitors to an area must be done responsibly.

VOA: special.2010.11.03

It helps reduce the number of high school drop-outs in Los Angeles and the San Francisco area.

VOA: special.2011.03.02

In the Forth Valley area the number of reported flu cases now stands at 672 per 100, 000 of population, compared with just 222 last week.

BBC: News Online

California-based RealtyTrac arrived at the figures by comparing the number of households in a metro area with the number of foreclosure filings.

NPR: Home Foreclosure Rate Surged in 2007

Navy Area is the number one priority of the Navy and Marine Corps among the different Theater Missile Defense systems.

CENTERFORSECURITYPOLICY: Center for Security Policy | Decision to Cancel Navy Missile Defense Program Should be Reversed and New Management, Willing to Deploy Sea-Based Systems, Hired