Feed as many as he/she will eat in a 15-20 min (might be just 15min) time period and then remove any uneaten crickets as they can stress out your gecko. 
Red 
>>Last sunday I purchased my first leopard gecko and I was wondering how much i should feed him/her(too young to sex). I know that as a juvenile they should be fed daily and have the crickets dusted with calcium but how many should they get per feeding? I've been feeding 5-6 crickets a day. thanks
-----
Crested Gecko Zeek:1.0
LEOS: Boo: 1.0 normal , Bronx & Nala: 1.1 blizzard,
Lily: 0.1 patternless, Abby: 0.1 albino, Zoe: 0.1 reduced pattern, Dot: 0.1 hypo
Chip: 1.0 papillion (small dog)