At first glance, Excel's ISNUMBER seems almost too straightforward to be useful—it simply tells you if a cell contains a numerical value. However, its true power lies in its ability to act as a ...

Italian economist Vilfredo Pareto noticed in the 1890s that 80% of Italy’s land was owned by 20% of its people. The same lopsided pattern shows up almost everywhere — sales (80% of revenue from 20% of ...