How to set up a time Sheet on Excel to restrict entry to only allow 5 workdays instead 7

[opera6th]

I am setting up a time sheet for my employers to use. There are 7 days in a week but I want to set it up in such a way that the user can only input work hours for 5 days a week and prohibit them from inputting anything on the other 2 days. For example, if Employee A worked Mon-Fri, then the user (employer) can enter the work hours for Mon-Fri but are not able to enter work hours for Sat and Sun. I want those cells to be inactive/prohibited.

Is there a formula where if ANY 5 cells are active, the other 2 will be inactive/prohibited?

[Butcher1]

Does formatting Monday thru Friday's cells as unlocked, then protecting the sheet (through the review tab) and not allowing selecting of locked cells work for you?

[opera6th]

No, I am not allowed to do that. Actually, I thought about using =COUNTA function but my data validation isn't working on my worksheet. I think it's because I'm using the time format when I enter values into the cell? Do you know anything about this?

[Butcher1]

COUNTA would still count a time format. I am out of ideas on this.

[opera6th]

Can you figure out why this is not working? Why I am able to allow to input values totaling over 60?

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