A: 1. In total Inuyasha's group collected 13 jewel shards before they were stolen by Naraku. (Miroku collected three on his own before giving them to Kagome).
2. Naraku collected all but thirteen of the shards on his own; the first ten collected by Inuyasha's group were given to him by Kikyo while he stole the remaining ones to complete the jewel.
- From InuYasha Wiki.