 The sets of positive real numbers and negative real numbers are often noted R+ and R−, respectively; R+ and R− are also used.The non-negative real numbers can be noted R≥0 but one often sees this set noted R+ ∪ {0}.In French mathematics, the "positive real numbers" and "negative real numbers" commonly include zero, and these sets are noted respectively ℝ+ and ℝ−.