This is the second part of a two part sign, the first being the number of ninths (E.g. 1 for 1/9); then angle hand downwards at wrist while changing handshake to sign nine.
Starting with pointer, middle and ring fingers and thumb extended from fist, palm towards you, and thumb pointing up. Twist hand at wrist so that palm ends pointing forward, thumb pointing downwards.
Extend thumb, pointer, middle and ring fingers from fist, thumb pointing up. Touch extended pointer finger to the ring finger of dominant hand. Flick dominant hand upwards in an arc.