Have you ever imported data into Excel that won’t calculate? Look at this example where the earnings look like numbers to the human eye, but not to Excel. And when Excel is not able to identify any numbers, it can’t calculate any sums or averages either.
This happens all the time if you use data from other data sources: It could be a txt-file from a booking system, a copy-paste from a website or even a database export.
Enough about the problem. Let’s solve it, and let’s not spend more than 2 minutes doing it!