Which three-digit number, made of consecutive digits, like 567, is 2 less than a cube and 2 more than a square?

Can you find out the missing number in the grid?

What's the next in the series?

H, Be, F, S, Mn, Kr, In, Gd, Tl, ?

Forwards I am heavy, backward I am not. What am I?

Arrange the numbers 1, 2, 3, 4, 5, 6, 7, 8 and 9 above and below the division line in a manner that the thus formed fractions equal to 1/3.

(You can use one number only once)

What do you call a fish without an eye?

When I got four, I have it none.
When I got two, I have it some.
When I got none, I have it all.

What is it?

The first box has two white balls. The second box has two black balls. The third box has a white and a black ball.

Boxes are labeled but all labels are wrong!

You are allowed to open one box, pick one ball at random, see its colour and put it back into the box, without seeing the colour of the other ball.

How many such operations are necessary to correctly label the boxes?

It has five wheels, though often think four, You cannot use it without that one more, You can put things in it, you can strap things on top, You can't find it in the market, but you can still go shop. What is it?

When can we add 2 to 11 and get 1 as the correct answer?