I've forgotten the gesture for 7, but the one shown here may be right. 9 is also a hand-gesture which mimics the curve of the traditional character for the number 9. In addition, 8 should point down (it mimics the actual chinese character for eight, which 'opens down') and 10 is also, or generally (forgot which) shown by crossing the index and middle fingers over to make an elongated 'x' which also mimics the chinese character for 10. Therefore, 2 looks like '3' (to us) with the index finger folded over the thumb which touches the palm.
North-east Asians count 1, 2, etc., by folding their fingers into their palm starting with their thumbs.
