high frequency data calculation

Hi guys,

I am a complete beginner in Excel VBA, encountering a difficult problem. Your help would be much appreciated.

Suppose you have a large database, which consists of high frequency minutes data, you need to calculate differences in values between each different time intervals, e.g. from 1 min to 10000 mins.

the format is looked like below

1 min aaa
2 min bbb
3 min ccc
4 min ddd
.................
......................


More specifically, what I am supposed to do is to calculate aaa-bbb, bbb-ccc, ccc-ddd, and then aaa-ccc, bbb-ddd, and then aaa-ddd and so on.

I know the VBA has a function to do repeated executions but am not sure how to adjust the time intervals.

It probably is a very easy problem. Please let me know if you know how to solve it.

Thank you.