Ratios[list] gives the successive ratios of elements in list. Ratios[list, n] gives the n\[Null]^th iterated ratios of list. Ratios[list, {n_1, n_2, ...}] gives the ...

RawBoxes[boxes] is a low-level construct which is formatted as boxes without further interpretation.

As of Version 6.0, Raw is no longer supported.

ReadList["file"] reads all the remaining expressions in a file and returns a list of them. ReadList["file", type] reads objects of the specified type from a file, until the ...

Read[stream] reads one expression from an input stream and returns the expression. Read[stream, type] reads one object of the specified type. Read[stream, {type_1, type_2, ...

ReadProtected is an attribute that prevents values associated with a symbol from being seen.

RealDigits[x] gives a list of the digits in the approximate real number x, together with the number of digits that are to the left of the decimal point. RealDigits[x, b] ...

RealExponent[x] gives log_10 (|x|).RealExponent[x, b] gives log_b (|x|).

Real is the head used for real (floating-point) numbers.

Reals represents the domain of real numbers, as in x \[Element] Reals.