Don't worry: Excel does all the calculating. Your job is to place the numeric data on the worksheets so that Excel can do its thing. You also must specify formulas so that Excel can compute results for you, which does require at least some knowledge of math. Many people use Excel for common household actions, such as tracking exercise routines and grocery lists. Excel is not just for accounting and mathematical applications. You will learn in the next hour how to specify formulas. There, you will see that Excel provides a lot of help along the way and can even guess at many calculations, such as totals, that you routinely need in your worksheets.
Do I always enter the time along with the date?
You can enter a time value, a date value, or both. Excel turns the information into an internal shortened format. (You can change the display format if you want to make the data look better.) If you don't enter a date with a time value, Excel accepts the time value only and tracks just the time. If you enter a date, Excel tracks only the date.