There is a square of a particular number which when doubled, becomes 7 more than its quarter.

Can you find the number?

A father's child, a mother's child, yet no one's son.

Who am I?

A bag contains 64 balls of eight different colours. There are eight of each colour (including red). What is the least number you would have to pick, without looking, to be sure of selecting 3 red balls?

Which word is least like the others? Third, fourth, fifth, sixth, seventh, eighth, ninth?

Three doctors said that Bill was their brother. Bill says he has no brothers. How many brothers does Bill actually have?

Can you divide the below-given shape into four equal and identical pieces?

Given below is simple addition with a defined pattern pattern:
7 + 7 = 2
8 + 8 = 4
8 + 5 = 1
6 + 9 = 3
10 + 11 = 9

Can you analyze the pattern and find out the answer for:

4 + 9 = ?

Two in a corner, one in a room, zero in a house, but one in a shelter. What am I?

Until it is measured, not known. Yet how you miss it when it has gone. What is it?

Below, you will find the mathematical proof that 10 equals 9.99999?. But is that possible or there is something wrong about it? Can you find the error?

x = 9.999999...
10x = 99.999999...
10x - x = 90
9x = 90
x = 10