If eleven plus two equals one, what does nine plus five equal?

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?

Can you find the least possible number such that

If the number is divided by 3, it gives the remainder of 1;
If the number is divided by 4, it gives the remainder of 2;
If the number is divided by 5, it gives the remainder of 3;
If the number is divided by 6, it gives the remainder of 4.

There are six people in a family namely M, N, O, P, Q and R.

R and O are brother and sister.

N is the brother of Q's husband.
P is the father of M and grandfather of R.

How many male members are in the family?

What is the Surname of Barbie Doll?

Consider this about a word: The first two letters signify a male, the first three letters signify a female, the first four letters signify a great, while the entire world signifies a great woman. What is the word?

What Deficiency does the below rebus represent?

VIT_MIN

Place the numbers from 1 to 9 in the circles in a manner that each side of the triangle sums up to 17.

I am under you when I am whole.
I shift above you if you remove the first letter.
I come all around you if you remove the second as well.

Can you tell me who I am?

Can you count the number of matches in the picture below ?