Variable names begin with a letter. Characters following the first character may be digits. (“R12” is a legitimate variable name, but “4everYours” is not.)
Real Answer™ distinguishes between upper and lower case letters, so “t” would be distinct from “T”.
Variable names may have up to 255 characters. All of a name’s characters are examined by Real Answer to distinguish that name from names of other variables, although when the Real Answer program prints variable names in its output, it sometimes shortens them if they are long.
Variables can take on the same range of numeric values that numbers can in Real Answer.
Variables introduced in the Answers & Scratch window start out with an initial value of zero if you don’t set them to something else. Variables introduced in the Equation Set window start out with an initial value of 0.000001 if you don’t set them to something else.
“π”, “pi”, “PI”, and “Pi” all refer to 3.141592653589793. The character “π” is obtained by holding down the option key while typing the “p” key.
“e' refers to 2.718281828459045, but may be overridden by another use if you choose. (Don't confuse the use of a variable named “e”, or the built-in constant “e”, with the use of “e” inside a numeral formated in scientific notation, e.g. “1e3” which means 1000.)
