Replace the question mark with the correct number.

2 + 2= 4
3 + 3= 18
4 + 4= 48
5 + 5= ?

What goes up but never comes down?

Which Travels Faster? Solve below famous picture riddle:

The cream is heavier than Milk. True or False?

Can you calculate the probability of getting a sum of six when a dice is thrown twice?

Find a 9-digit number, which you will gradually round off starting with units, then tenth, hundred etc., until you get to the last numeral, which you do not round off. The rounding alternates (up, down, up ...). After rounding off 8 times, the final number is 500000000. The original number is commensurable by 6 and 7, all the numbers from 1 to 9 are used, and after rounding four times the sum of the not-rounded numerals equals 24.

You walk into a room that contains a match, a kerosene lamp, a candle and a fireplace. What would you light first?

By removing one matchstick and adding one matchstick, can you convert the word "ZOO" to an animal name?

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 has 13 hearts but no other organs?