Ordinal Endings With Mathematical Expressions: Ordinal endings are formed by attaching "st," "nd," "rd," or"th" to a numeral or other mathematical expression. If the "n" or the "r" is omitted from an ordinal ending in print, it must be omitted in braille. The contractions for "st" and "th" must not be used. Ordinal endings are part of a mathematical expression and must be punctuated mathematically.
 1st, 2nd, 3rd, and 4th.
 1st, 2d, and 3d.
