is there a way to modify formulas based on inputs?

let's say i want to sum 4 rows in one column. so i'd type something like =SUM(A1:D1)

but what if i want to suddenly sum 10 rows? i'd have to go in and re-type the formula to =SUM(A1:J1) or drag that box to sum more rows.

i'm wondering if there's a way i could type in a number in a cell, and a formula could use that to determine how many rows to select.