Which Number is the odd one out?

A) 7145
B) 2716
C) 5321
D) 4135

You are given with the following sum. Each of the letters can be decoded as a digit. If we tell you that D = 5, then can you solve it entirely?

DONALD
+GERALD
=ROBERT

Can you arrange four 9's and use at most 2 math symbols, to make the total 100?

If a wheel has 54 spokes, how many spaces are there between the spokes?

There are forty elephants and they have forty-fore heads. How can this be possible?

In a basket of apples,
when counted in twos, there was one extra
when counted in threes, there were two extra when counted in fours, there were three extra
when counted in fives, there were four extra
when counted in sixes, there was five extra.

However, if the apples were counted in sevens, no extra apple was left. Can you calculate the minimum number of apples that were present in the basket?

The doctor prescribed you to take one pill from the bottle every half an hour. The bottle is now left with only three pills.

How long do you think you have before you run out of pills?

What brings you down but never up?

I am white when I am dirty, and black when I am clean. What am I?

A maths symbol is hidden in the below Bar Graph. Can you decipher it?