Personal identity card and telephone number information processing

First, the identity interception date: TEXT (MID (C3,7,8), "00-00-00")

MID function: from 7 starts, the interception of a string of 8

TEXT function: to convert the format character is "00-00-00" format

Note: setting cell format: text box, and then enter the card 18

Second, the 12-digit phone number hidden fourth or 7

Format: SUBSTITUTE (text to replace the old, new text, [replace the first few])

           SUBSTITUTE (B2, MID (B2,4,4), "****", 1), taken out of the cell A1 is replaced with the 4-digit first occurrence **** four digits (13,710,001,000 = 137 **** 1000)