Quickly Solve this riddle

7 - 4 + 3 * 0 + 1 = ?

Imagine a box with two cogwheels, one big with 24 teeth and one small with 8 teeth. The big one is firmly attached to the center of the box which means it does not turn or move while the small one rotates around the big one.

How many times do you think that the smaller wheel will turn compared to the box when it turns once around the big one?

Can you find out the remainder when 3^300 is divided by 5?

Use only one mathematical symbol and all numbers (0-9) to get a sum of 99

I went to the bookshop and spent one-half of the money that was in my purse.

When I came out, I found that I had as many cents as I had dollars and half as many dollars as I had cents when I went in. Find the money in my purse when I entered the store.

Queen Elizabeth organised a royal party.

To Avoid uninvited guest royal family set a password.
Jack (an uninvited person) plan to enter the party. He stand nearby the door.

First guest comes, the security person said 'twelve' and guest replied with six.
Second guest comes , the security person said 'six' and guest replied with 'three'.

Jack thought is enough and he walked to the entry point. The security person said 'eight' , Jack replied smilingly 'four'.
He was immediately thrown out of the party. why ?

You see a mathematical expression in the picture. Can you think of a movie that this expression refers to?

What number do you get when you multiply all of the numbers on a telephone's number pad?

You need to remove two matchsticks to make the below equation true. Can you do it ?

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