is there any formula that let's you sum all the numbers before the number you
select?

for example,
Col 1 Col 2
1 5
2 2
3 9
.....

so if the number 9 is chosen then it adds 9+2+5 or if 2 is chosen then it
adds 2+5. Keeping in mind that there are X numbers so the list could have
1600 numbers.

thanks.