A girl counts to five on one hand, raising one finger per count, and ends on an open hand. Generated hands are hard in a still and harder in motion: the finger count has to go up by one at a time and the hand has to keep five fingers while it does.
The clip is 3 seconds, so five counts come at roughly one every 0.6 seconds; the prompt says she counts quickly. Score the hand, not the speed.
A girl of about eight sits facing the camera in front of a plain yellow wall and counts from one to five on her right hand, raising one more finger on each count: index finger, then middle finger, ring finger, little finger, and finally her thumb, so she ends holding up an open hand with all five fingers spread. She counts quickly; the whole count fits in three seconds. Medium close-up, steady camera.