Wikipedia:Styletips/34
Hanging hyphens
A hanging hyphen is used when two compound modifiers are separated (two- and three-digit numbers, a ten-car or -truck convoy, sloping right- or leftward, but better is sloping rightward or leftward).
A hanging hyphen is used when two compound modifiers are separated (two- and three-digit numbers, a ten-car or -truck convoy, sloping right- or leftward, but better is sloping rightward or leftward).