What is the formula of whole column summation or whole row summation in excel? How to find the average?

What is the formula of whole column summation or whole row summation in excel? How to find the average?

For example, the data is in a1:a100
Sum: = sum (A1: A100)
Average: = average (A1: A100)
For the whole line, just change the data area
For example, A1: F1