What goes up but never comes down?

What jumps higher than a building?

A half is a third of it. What is it?

Which side of a cat has the most fur?

What is more useful when it is broken?

I can write cow in 13 letters. Can you?

I grow up while growing down. What am I?

What is black and white and red all over?

If 1/2 of 5 is 3, then what is 1/3 of 10?

What has ten letters and starts with gas?

Prove that taking away 1 from 19 makes 20.

How many times can you subtract 6 from 30?

I place today before yesterday. What am I?

What is the timepiece that needs no winding?

How many birthdays does the average man have?