Why is the Hole below a Lock?

Assume there are approximately 5,000,000,000 (5 billion) people on Earth. What would you estimate to be the result, if you multiply together the number of fingers on every person's left hand? (For the purposes of this exercise, thumbs count as fingers, for five fingers per hand.) If you cannot estimate the number then try to guess how long the number would be.

Can you move two match sticks to make it 430?

The teacher told the student that if he told a lie then he will be expelled from school and if he told the truth then he still is expelled from school.

What can a student say to prevent his being expelled from school?

If,
9 * 8 * 7 = 65
8 * 7 * 6 = 50
7 * 6 * 5 = 37

Find
6 * 5 * 4 = ?

Can anyone tell me a word in the English dictionary which has a silent 'z'?

What has 13 hearts but no other organs?

What has one letter and starts with an E?

What is the Surname of Barbie Doll?

Can you find out which options fits best with the missing column?