I am trying to find a formula that calculates total hours for employee scheduling purposes.

I figuered out how to calculate a total for time in - time out involving two cells vertically. For example: On Monday - Cell A1 (10:30am time in) Cell A2 (3:00pm time out) for total hours scheduled 4.5 hours. Now I need a formula that calculates total hours for week involving multiple cells horizoncally.

For example:

Monday, Tuesday, Wednesday, Thursday, etc....
A1,A2; B1,B2; C1,C2; D1,D2; etc....

I know this is possible because I used a template that did this function in the past. But I can't remember how to do this.

Grateful for any help!!