Four. The number four has four letters, making it self-enumerating. Interestingly, there are no self-enumerating numbers in French.

The word rendezvous. Even though it’s a French word, it’s in the English dictionary and is pronounced [rahn-duh-voo].

Turns out rendezvous isn’t the only one. Another word is oyez.

Piano keys, keyboard keys, monkey, donkey, turkey, jockey, hockey, doohickey, malarkey and passkey. There may be others, but you get the drift.

(3 + 3) / .3 = 20