Answer:
Handy when you need to measure something or run a kingdom.
I'm a ring of sliced onion dipped in batter and then deep fried.
When is 1500 plus 20 and 1600 minus 40 the same thing?
If you are unsure how to use one then just ask a flight attendant.
White and thin, red within, with a nail at the end. What is it?
The sun bakes them, The hand breaks them, The foot treads on them, And the mouth tastes them. What are they?