The @ symbol can also appear in regular formulas outside of tables when Excel thinks you're trying to reference a single value from a range. If you see it pop up unexpectedly, it usually means Excel ...

Professor Raúl Rojas has published a book about how symbols have been used throughout history in mathematics. The work was translated into English this year.

REDUCE allows you to iterate through your data, building your result step-by-step, in the same way a loop operates in a ...