Question datagridview input values and find the sum

[komr]

Hi all!
I am a beginner in vb.net. I create a window form with a dataGridview in it. There are two columns , say X-value and Y-Value columns. I want to input values in each cell and then find the sum or average of each column. I don't know how to do this. Please help me with a simple and easy-understood code. your help is highly appreciated.

Thanks!