What is the fewest number of coins that would be required in order to make sure each and every coin touches exactly three other coins?

In 1990, a person is 15 years old. In 1995, that same person is 10 years old. How can this be?

You see a mathematical expression in the picture. Can you think of a movie that this expression refers to?

Christina has four daughters, and each of her daughters has a brother. How many children does Christina have?

Two fathers and two sons went fishing one day. They were there the whole day and only caught 3 fish. One father said, that is enough for all of us, we will have one each. How can this be possible?

13 decks of cards have been mixed. What is the minimum number of cards that must be taken out from the above-mixed cards to guarantee at least one 'four of a kind?

Which English verb becomes past tense just by rearranging the letters?

Can you name an animal whose killing cannot be performed without spilling your own blood?

Take number 1000 and then add 20 to it.
Now add 1000 one more time.
Now add 30.
Now add 1000 one more time.
Now add 40.
Now add 1000 one more time.
Now add 10.

What is the total?

You need to climb ten stairs. At every stair, you can either take one step up or you can jump two steps up.

In how many different ways you can climb 10 stairs?