If I understood you well, using your picture as example, you want the sum of the "Total Hours" of each day for a specific "Week Number"?
I don't know how your app was built, so the best solution I can give you is this formulae:
Sum(Filter(cltYourCollection;WeekNum(yourDate) = WeekNum(currentDate));'Total Hours')
Basically, you're giving the "Sum()" function a table of all records whose week number is equal to the week number you're looking for. The second parameter should be the column corresponding to the "Total Hours" (it's also an expression, so you can put in an arithmetic operation such as an addition of multiple columns if you need).