( by CC Coach )
I'm using Chrome on a Mac.
Screenshot of the Spreadsheet:
Format all your cells as Plain Text, in which you have put the values as mm:ss and then put the values. And also format the cells in which you want the results as mm:ss
So now Cell E20 will have the result as 5:39
And similarly you can manipulate any of the cell and convert it to mm:ss format.
I hope the above solution will help you, and if you need more help then please do comment below on this blog itself, I will try to help you out.