Calculations are only available for text fields and are accessed through the Text Field Properties dialog. In reality all three are JavaScript but for the first two Acrobat builds the JavaScript code for us. Once we have the sum we simply divide this value by the length of the array.
Count how many numbers there are.
Finding the average value of a group of numbers is as easy as summing all of the numbers and dividing by the total number of numbers. So the average is 6. JavaScript has a built-in calculator and mathematical operations can be done directly in the console.