Meant to clarify that the 3 day Angkor pass is good for any 3 days in 10 from issue date, which probably was clear from the context, but... That is, you don't have to do a 3 day consecutive death march as we had to in the old days.
Make sure your guide shows you the Apsara showing her teeth, there's only one. I've got a guide recommendation, if you want one.