Greek letters were introduced into mathematics long ago to provide a collection of useful symbols to stand for abstract objects, such as numbers, sets, functions, and spaces. At the time they were introduced, most scholars had been taught some Greek during their education, so the letters were familiar. Today, outside of the Greek community, these symbols may seem quite foreign, and difficult to remember. The table below lists all of the letters in the Greek alphabet, upper-case and lower-case, with their names and pronunciations. The lower-case letters are most often used for variables, such as angles and complex numbers, and for functions and formulas, while the upper-case letters more commonly stand for sets and spaces.