If you’ve ever built a running total in Excel, you’ve probably written something like {=SUM(A$1:A2)} and dragged it down the column again and again. It’s a simple enough approach—until your dataset grows or starts changing frequently. At that point, keeping everything accurate can turn into a hassle. Creating a table in Excel or using dynamic ranges can make things a bit easier, but they don’t completely solve the problem. You still end up copying formulas, expanding ranges, and hoping nothing breaks.