What is the purpose to using functions in Excel?

Answer 1

Functions are in-built formulas to do specific tasks. They are useful for doing specified tasks quickly and simply. Excel has hundreds of functions that can be used. They are categorised for different uses, such a Financial functions or Date and Time functions. If you are writing formulas in Excel you would use a lot of functions. Using Excel without using functions would make things very slow. See the related question below.

Answer 2

Functions are built-in formulas in a spreadsheet. They save people the time of having to do common operations in a long winded fashion. You could add a list of numbers like this:

=A1+A2+A3+A4+A5+A6+A7+A8+A9+A10+A11+A12+A13+A14

That will work, but it is very slow. If you had a 100 numbers to add, it would be even longer. Adding long lists of numbers is something that is done regularly in a spreadsheet so a built in formula is provided to make it easier. You can do the formula like this instead using the Sum Function:

=Sum(A1:A14)

That will add up the 14 numbers. If it was 100 numbers the formula using the Sum function would be:

=Sum(A1:A100)

Adding a list of numbers is a simple thing, but there are lots of complex operations that are regularly done in spreadsheets, like calculating interest on a loan, that can be done simply with a function. You also know that the function is more likely to do it correctly than if you try to do it as a long complex formula yourself. So that is why there are functions in a spreadsheet.