What's the best place to go shopping in the ocean?

Can you find the missing letter in the sequence?
S - T - I - L - ? - T - F - Y - C

I cry without having a voice.
I fly without having wings.
I bite without having teeth.
I whisper without a mouth.

Who am I?

Considering the below equation:

V + II - VI = 10
IV - X + VIII = 20
IV - VII + VI = 30

Then, I + II + III = ?

I speak without a mouth, and hear without ears. I have no-body, but I come alive with the wind. What am I?

Arrange the numbers 1, 2, 3, 4, 5, 6, 7, 8 and 9 above and below the division line in a manner that the thus formed fractions equal to 1/3.

(You can use one number only once)

I cannot talk, but I always reply when spoken to. What am I?

Name the three-letter word that can complete the below words:

A) L O _ _ _ E
B) E D U _ _ _ E
C) _ _ _ E R
D) _ _ _ T L E

How many letters are in the alphabet?

What is the largest amount of money that you can possess in change and still if someone asks you for a dollar, you won't be able to give?