Pecoflyer, I liked your answer at first but I just reread his question and I think we both misunderstood. Your answer is correct if 1.25 means one and a quarter minutes; the conversion you recommend will produce a result of 1:15. But now that I read more carefully, I think what he's saying is that 1.25 means 1 min 25 sec. If that's so, maybe the solution is simpler:

Big0, who writes the times into this spreadsheet? If it's you, for 1 min 25 sec don't enter "1.25", enter "0:1:25". To Excel that means 0 hr, 1 min, 25 sec. And, as Pecoflyer said, make sure those cells are formatted as "mm:ss", or perhaps as "[m]:ss", so that they'll be displayed properly. Then calculations you do with the time values should work correctly.

That's assuming you want the spreadsheet to work immediately, at courtside. If you're just entering the times at the game and have leisure to work out the totals afterward, then it's probably easier to enter "1.25" at the time and convert them to something you can do proper arithmetic with later. We can tell you how to do that, but I'm guessing you want the results right away, and if so you need to use the colons and the leading 0 so that Excel will know you're talking about minutes and seconds.

There is another possibility: You can have one cell for minutes and the next one for seconds. Using that, you can enter 1<Tab>25, and have the worksheet set up to convert that to 1:25.