How can you write nineteen in a manner that if we take out one, it becomes twenty?

Prove that twice of ten is the same as twice of eleven.

You have two buckets - one holds exactly 5 gallons and the other 3 gallons. How can you measure 4 gallons of water into the 5 gallon bucket?

(Assume you have an unlimited supply of water and that there are no measurement markings of any kind on the buckets.)

Can you solve this amazing hard number series problem?
7, 8, 10, 12, 16, 18 ?

O_er_t_o_

Complete the missing letters of the given word.

I am a normal creature, but I have five hands. I can even have more but even then I will be considered normal.

Who am I?

What is the next number in this matchsticks series riddle?

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

Explain how?

I am a ten letters word
The first four letters have the power to rule,
Next, four-letter can be eaten.
The next three-letter represents a lady.
I can fly as well

what am I looking for?

There are three houses in a straight row. One is red, one is blue, and one is white. The red house is left of the middle. The blue house is right of the middle. Where's the white house?