What is the fewest number of coins that would be required in order to make sure each and every coin touches exactly three other coins?

Only one color, but not one size,
Stuck at the bottom, yet easily flies.
Present in sun, but not in rain,
Doing no harm, and feeling no pain.
What is it?

John bought 150 chocolates but he misplaced some of them. His Father asked him how many chocolates were misplaced.
He gave the following answer to him:
If you count in pairs, one remains
If you count in threes, two remain
If you count in fours, three remain
If you count in fives, four remain
If you count in sixes, five remain
If you count in sevens, no chocolate remains.

Can you analyze the statements and tell us how many chocolates were lost?

What is more useful when it is broken?

Count the number of triangles in the given picture.

You may enter, but you may not come in. I have space, but no room. I have keys, but open no lock. What am I?

who is silent in the parliament?

What brings you down but never up?

What is the coolest letter in the alphabet?

The following alphametic has only one solution. Can you find it?
ENLIST + SILENT + LISTEN = ANAGRAM

PS: You may start the number from 0.