I am trying to make the custom cell format change the display of a
number like 3.20 to 3:20
I tried ?0":" for a cell format but I cant get the decimal part to
work. I basically want it to look like a time format but not be one. If
I use mm:ss then it totally changes 3.20 into 4:48 Some time conversion
is applied.

0.":"_.00 was close. It shows 3.:20

I would appreciate any help.

Thanks
Scott