10+10 and 11+11 can give you the same answer.

Explain how?

A sundial has the fewest moving parts of any timepiece. Which has the most?

Place a mathematical symbol between the numerals 5 and 9 in such a way that the resulting number is greater than 5 but smaller than 9.

They are the five precious gems of an everyday sort and all can be found on a Tennis Court. Who are they?

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

Find the combined weight of the Cat, Dog and Rabbit in the given picture.

Can you solve this picture maths equation?

How can you make a TV, a bed, a dog, and a car liquid?

10 people came into a hotel with 9 rooms and each guest wanted his own room. The bellboy solved this problem.
He asked the tenth guest to wait for a little with the first guest in room number 1. So in the first room, there were two people. The bellboy took the third guest to room number 2, the fourth to number 3, ..., and the ninth guest to room number 8. Then he returned to room number 1 and took the tenth guest to room number 9, still vacant.
How can everybody have his own room?

I am beautiful, up in the sky. I am magical, yet I cannot fly. To people I bring luck, and to some people, riches. The boy at my end does whatever he wishes. What am I?