If you are working in a spreadsheet, which I assume you are, the correct format for two different functions put together is that there is only 1 equal sign put in front of the first function. For example, you have data in a1 to a7
You want to average the data and add this to the minimum value in a1 to a7. You can do it in two ways.
Method one
=average(a1:a7) + min(a1:a7)
Method Two
you can use the sum function
=sum(average(a1:a7);min(a1:a7))
No matter which way you choose, the answer will be the same and only the first function has an equal sign. If you put equal signs all over the place you get errors.