Areca Nut is used for eating directly as well as with paan (Betel Leaf)
Areca nut widely used in India is called as Paan or Supari. It’s consumed both as raw nut, as dried ripe nut (Chali supari), and as semi mature cut and processed varieties(like Choor, Bette, Saraku and Rashi).
After Puja they can be used for eating
They are placed in Puja in odd numbers As 7, 11,21