Dealing with Short Time format

[hawkins]

I have data that has been imported as short time. I am trying to find percent different for reliability sake. I am dealing with reliability in a utilities company and the duration is in short time , 1:03. I am trying to do an equation like this: ([CEMI3]/(1:03))*100. I am wondering if that will work correctly/is this the best way to go about this. Any suggestions will be greatly appreciated!

*Solved: I ended up using the Hour and Minute functions to take out those and created a new column that stored the converted value.