I am an odd number. Take away a letter and I become even. What number am I?

In the Chess Board picture below white army is arranged. You need to add a black army on the board such that no piece is under any threat.
Note: Army comprised of 1 king, 1 queen, 2 rooks, 2 bishops, 2 knights, and 8 pawns.

Today is John's birthday.
A year ago, John had five candles and he lit all the candles except the one at the last.
Now he is going to light all the candles.

How old is John Today?

(He is not five today.....)

You are given with the following sum. Each of the letters can be decoded as a digit. If we tell you that D = 5, then can you solve it entirely?

DONALD
+GERALD
=ROBERT

What begins with T, ends with T, and has T in it?

How many triangles are there in the picture below?

Can you divide the below-given shape into four equal and identical pieces?

Count the squares in the matchstick puzzle below?

There are 2 people near the river and both of them want to get on the other side. The boat can only take one of them. But they got across.
How?

I am the one who remains awake when you sleep. But I need to rest when you awake. Who Am I?