Film Frame counting system in Excel

In the movie business we count HOURS:MINUTES:SECONDS and the FRAMES Depending on where we are in the world, and what format we use, the are 24, 25 or 30 FRAMES pr. second We use Time Codes (TC) to illustrate this: 00:02:32:12 will be 0 hours, 2 minutes, 32 seconds and 12 frames I need a Excel sheet where I can MULTIPLY and SUBTRACT these TC's 00:02:32:12 + 00:02:06:20 = 00:04:39:08 (at 24 frames/sek)