Can you arrange four 9's and use at most 2 math symbols, to make the total 100?

John is the son of Jacob.
So,
Jacob is the_____of John's father?

If eleven plus two equals one, what does nine plus five equal?

If 1+9+8=1, what is 2+8+9?

Ten coins have been arranged as you can see in the given picture. In this arrangement, a triangle is formed pointing upwards. You have to invert the position of the triangle and make it point downwards while changing the position of 3 coins only. Can you do it?

What jumps when it walks and sits when it stands?

Two old friends, Jack and Bill, meet after a long time.

Three kids
Jack: Hey, how are you, man?
Bill: Not bad, got married and I have three kids now.
Jack: That's awesome. How old are they?
Bill: The product of their ages is 72 and the sum of their ages is the same as your birth date.
Jack: Cool..But I still don't know.
Bill: My eldest kid just started taking piano lessons.
Jack: Oh, now I get it.

How old are Bill's kids?

What word does this rebus represent?

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What word is pronounced the same if you take away four of its five letters?

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