I ran into an interesting scenario when a colleague of mine was setting up a list in SharePoint 2010. He was creating a list, with a phone number column, a phone extension column, and a calculated column for phone display. Things were working fine, until he entered some data and the display column didn’t look right. When he opened the settings for the phone display, he saw this in the formula: #NAME?-#NAME?After some tinkering, we got it to work by changing the name of the phone extension column. ......