Can you convert the number zero(0) into a positive number using just one mathematical operator ?

You are given 16 witch hats. The hats are divided in four different colours – red, blue, green and yellow. Every colour has been assigned to four hats. Now each of the hat will be glued with a label of an arithmetic sign – ‘+’, ‘-‘, ‘x’ or ‘/’. But you can label one sign only once on one colour. In such an arrangement, the hats can be uniquely defined by its colour and symbol.

Can you arrange all the 16 hats in a 4x4 grid in a fashion that no two rows and columns have a repetition of colour or sign?
We have arranged four hats in the below picture to assist you.

John said, "If yesterday was tomorrow, today would be Friday."

When did John make this statement?

By moving just one matchstick, you need to make the below statement true. Can you do it?

What does man love more than life, hate more than death or mortal strife; That which contented men desire; the poor have, the rich require; the miser spends, the spendthrift saves, and all men carry to their graves?

You are given four results as below:
1111 = F
2222 = E
3333 = T
Then, can you find out how to code 4444?

The below mentioned letters have been placed in a order using a logic.

DEAD, BALL, FEAR, SHOP

Can you find the logic?

Which is heavier: a ton of bricks or a ton of feathers?

What is always in front of you but can’t be seen?

Which flower has two lips?