Change Format of Cell into a Number (it thinks it's a date)

I am having slight trouble with the formatting of some cells. Every month I will be copying data into a row, the problem is Excel thinks it's a date instead of an integer of some sort.

The value copied will look something like this:
79:42:00
(meaning 79 hours and 42 minutes)

Excel is taking that and interpreting it as:
1/3/1900 7:42:00 AM

Is there an easy way to format this so Excel thinks it's a number (even if 79.7).

I tried to change the format of the cell to "Text", but it changes it to: 3.32083333333333

Thanks again!