Table listing all of the telephone area codes in North America with information such as when the area code was introduced, what area code(s) it replaced, and whether the replacement was an overlay or split.

So what just happened? I told Excel, “Here is a value in the left-hand column of my data. Now look through this range of cells, and in the third column to the right, find the value on the same row.” A lot like a phone book. So up next, I'll explai

For example, we have a set of phone numbers that have incorrect area codes in them. We want to replace each phone number’s old area code with a new area code, specified in the NEW column: We want to change the area code of 370, into the area code of 111