I am looking for a word that change both gender and number when i add the letter 'S'.

What Word am I Looking For ?

A beggar on the street can make one cigarette out of every 6 cigarette butts he finds. After one whole day of searching and checking public ashtrays the beggar finds a total of 72 cigarette butts. How many cigarettes can he make and smoke from the butts he found?

Why do people go to bed?

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

What animal walks on four legs in the morning, two legs during the day, and three legs in the evening?

Oedipus, the king of Thebes, figured out the answer to the riddle:

There are five vowels (a, e, i, o, u) in the English language.
Can you tell us a word that contains all these vowels?

What can jump higher than a building?

You and your two friends are working in a multinational company. How can you three find out the average salary of you all without disclosing your own salary to the other two?

Find the next number in the series?
2, 12, 36, 80, 150, 252, 392, _ ?

Can you move 2 matchsticks to form four equal sized squares.