I can do this creating a new column
=POWER(A1, 10) and then I get the result with
=AVERAGE(B1:B2). But how to do that without a new column?
You can use an array formula to do this. Let's say your numbers to set to a power are in cells
When you are done entering the formula, you need to press Ctrl+Shift+Enter to enter it as an array formula.