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

Can you start the fire using two pieces of wood?

After teaching his class all about Roman numerals (X = 10, IX=9 and so on) the teacher asked his class to draw a single continuous line and turn IX into 6. The teacher's only stipulation was that the pen could not be lifted from the paper until the line was complete.

What is black when you buy it, red when you use it, and gray when you throw it away?

A woman is sitting in her hotel room and hears a knock at the door. She opens the door to see a man whom she’s never met before. He says, “I’m sorry, I have made a mistake, I thought this was my room.” He then goes down the corridor and into the elevator. The woman goes back into her room and calls security. What made the woman so suspicious of the man?

Below the four parts have been reorganised. The four partitions are exactly the same in both arrangements. Why is there a hole?

If we add four times the age of John four years from now to five times his age five years from now we get ten times his current age.

How old will John be two years from now?

What can run but never walks, has a mouth but never talks, has a head but never weeps, has a bed but never sleeps?

What three numbers, none of which is zero, give the same result whether they’re added or multiplied?

How can you spell "White of an egg" in one word?
Hint: I know you can spell coke, poke, and joke.