Can you find out the missing number?

? 4 5 3 5

9 5 7 10 3

If you go to the movies and you're paying, is it cheaper to take one friend to the movies twice, or two friends to the movies at the same time?

What is the word or phrase?

A bag contains 64 balls of eight different colours. There are eight of each colour (including red). What is the least number you would have to pick, without looking, to be sure of selecting 3 red balls?

Can you Find and name the hidden bird in the picture below ?

I don't get anymore wetter, no matter how much rain falls on me.

What am I?

It's a protector.
It sits on a bridge.
One individual can see directly through it, while others wonder what it hides.

What is it?

You walk into a room that contains a match, a kerosene lamp, a candle and a fireplace. What would you light first?

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.