What 4-letter word can be written forward, backward or upside down, and can still be read from left to right?

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 solve this amazing hard number series problem?
7, 8, 10, 12, 16, 18 ?

The two towns are exactly 100 km apart. John leaves City A driving at 30 km/hr and Jacob leaves City B half an hour later driving at 60 km/hr. Who will be closer to City A when they meet?

Spelt forwards I’m what you do every day, spelled backwards I’m something you hate. What am I?

What is the riddle which can be asked all day with a different correct answer each time.

One of the leprechaun is missing if you see the two pictures attached to this question. Where did he go? When he comes back, do you know where has he been?

Can you count the number of matches in the picture below ?

What's the next in the series?

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

What has one eye, but can’t see?