I'm doing a fall externship (meaning for academic credit) this upcoming semester. I have to complete 540 hours of work to receive credit. How do I set up a spreadsheet that allows me to enter in my clock in, lunch out, lunch end, and clock out hours every day without me having to manually calculate the hours I worked, and then subtract my daily hours from the total of 540? For example, let's say I clock in at 8:30, lunch out at 12:30, my lunch ends at 1pm, and I clock out at 5pm. I want Excel to calculate that I worked eight hours that day and then subtract 540 - (daily hours worked cell) = hours remaining of externship (540 - daily sum earned, which here is 8 = 532). Then the next day, 532 - 8 = 524, and so on.