Combin function number probabilities

[Kenokeen]

Hi,
I am having difficulties setting up excel with combin to determine number probabilities.
My issue is determining
Out of 80 numbers 20 are drawn
I have 40 numbers chosen what are my probabilities of matching the 20 out of my 40?

I can't figure out if or how combin will work for this question
Any help or suggestions would be amazing
Cheers

 

[stapel]

I am having difficulties setting up excel with combin to determine number probabilities.
My issue is determining
Out of 80 numbers 20 are drawn
I have 40 numbers chosen what are my probabilities of matching the 20 out of my 40?

Does "combin" mean "combination"?
Are you trying to match all of the twenty drawn from the forty chosen?

When you reply, please provide the full and exact text of the exercise, the complete instructions, and a clear listing of your thoughts and efforts so far. Thank you!