What is a tax ID number? It's a unique nine-digit number issued by the Social Security Administration or the IRS to anyone who pays taxes. Learn more here.

Build, read, write, and represent three-digit numbers using base-10 blocks and symbols. Build, read, write (in standard and expanded form), and represent three-digit numbers using base-10 blocks and ...

In many parts of the US, it has long been possible to make local calls with just the seven-digit phone number; the three-digit area code was implicit for calls between numbers using the same area code ...