Find out a multi-digit number that if multiplied by the number 9 or any of its multiplications products (i.e. 18, 27, 36, 45,..) will result in the multiplication factor repeated (n) number of times.

Look at this sequence from top to bottom. What is the next number in the sequence?
1
11
21
1211
111221
312211

Can you find out the smallest number that can be conveyed as the sum of three squares in three unique ways?

What kind of tree can you carry in your hand?

Using Only Five 5's and any mathematical operator make sum as 37

What has 88 keys?

There were five men at church, and it started raining while they were outside. The four that ran still got wet, but the one that was still stayed completely dry. Why did he stay dry?

Which alphabet letter is a question?

My friends called me Iron59 because my parents are a chemist and a mathematician. What is my real name?

A river should be crossed by a father, a mother and their two sons and two daughters.
There are some rules that should be followed while crossing the river. There can be only two people in the raft while crossing. The daughters cannot be with their father unless there is the presence of the mother. The sons cannot be with their mothers unless the father is present. Unless the guard is on the board, the criminals cannot be with any of the family members. Only the adults like the father, the guard, and the mother knows to use the raft.

How will they cross the river?