Elapsed time calculation

[kecocontrols]

I have a hours:minutes columns that I need to subtract from each other to get elapsed time in.

Example: a6 – a5 =?

on a basic subtraction I get a value error
a1 = 11549:06
a2 = 11573:06
a3 = 11597:06
a4 = 11621:06
a5 = 11645:06
a6 = 11669:06

It seems that Excel 2007 has trouble with HHHHH:MM format. I would be willing to work with a column were the minutes are stripped off. Then it becomes just a simple subtraction.

[gebobs]

I like it when folks answer their own questions. Good job.