Is there some kind of formula that can sum an amount or rows based on a number you type in? Like if for example, I want to sum only 50 rows one time, 300 another, 1000 yet another and so on is there some way I can do this without having to highlight different sections to see totals? Ideally if I could just type in 50 and it sums the first 50 rows in a specified column and then the same for any other number that is typed in. It would always start from the top.