For me:
21: L shaped and bend the thumb twice.
22: V shaped 2, and bounce twice
23: 3 shaped, bend middle finger
25: 5 shaped, bend middle finger
24, 26 to 29: L shaped 2, followed by the number (L4, L6, L7, L8, L9)
V shaped 2 for 23 to 29 are accepted too. When I first learnt ASL numbers, I...