Can you replace the question mark with the correct number?

What does Alexander the Great and Winnie the Pooh have in common?

Two natural numbers have a sum of less than 100 and are greater than one.

John knows the product of the numbers and Jacob knows the sum of numbers.

The following conversation takes place between them:
John: 'I am not aware of those numbers.'
Jacob: 'I knew you wouldn't be. I am not aware myself.'
John: 'Now I know them!'
Jacob: 'Now I know them, too!'

What are the two numbers?

If 5 cats catch 5 mice in 5 minutes, how long will it take one cat to catch a mouse?

I have one of the three numbers: 1, 2, or 3 in my mind. I speak only truth. You can ask me just one question for which I will only reply in yes or no or don't know. What question will you ask from me so that you are able to know the number?

What came first, the chicken or the egg?

Can you count the number of squares in the figure below?

This is a classy optical illusion puzzle. What more you can find except bricks in the image below?

How many Watermelons are there in the below picture?

How can you leave a room with two legs and return with six legs?