Time Log daily hours error when no time entered

I made a Time Log in Numbers. I have multiple clock in and clock out time slots per day. The formula runs correctly when there is time in the slots. When time is not in the slots there is an error that occurs in the total at the bottom of my spreadsheet. I just want to display it as blank if there is not time in the slots so its ready to calculate whenever I add time into that new day's slot.

Below you can see 4 of the [ Hours ]'s cells have the same formula and are working. (Row 7 is empty)

BUT

When the formula shows 0.0, the total, at the end of the sheet, is broken. The simple formula that is in the [ TOTAL Hrs ] cell is SUM(G3:G28). This is all the [ Hours ] totaled up together.

It doesnt like that 0.0. When the formula in the 0.0 cell is removed, it is happy:

My sad attempt at a fix:

IF I don't put the calculation in the empty slots' [ Hours ] cell, then my time total at the end is happy. But WHAT A HASSLE to have to drag the code down into the next days' cell to calculate and add the time to the total hours cell at the bottom of my sheet...

What formula can I use in ALL the [ Hours ] cells - one that I can drag down into all the rows awaiting time to be entered?

This one I tried but even if there is time in the slots, it says I worked 0 hours. This is the right kind of concept I'm looking for - but it needs the "else" statement I dont understand how to write in.

My DREAM code would say: If the time slots are empty, dont show anything in that [ Hours ]'s cell. BUT if there is a time in there, display the total hours and mins logged. This code would not break the simple [ TOTAL Hrs ] cell at the bottom.

Can you help me? Clearly this isnt my forte.

Thanks!