Kai: To remember how many feet are in a mile, you just gotta use "five tomatoes".

 Kai: Five tomatoes sounds like five, two, eight, o and there are 5,280 feet in a mile. 

Taehyun: To remember how many meters are in a kilometer you just remember "1,000" because the system of measurement in the rest of the world wasn't invented by a drunk mathematician rolling dice.