Can you convert the number zero(0) into a positive number using just one mathematical operator ?

A girl is twice as old as her brother and half as old as her father. In 50 years, her brother will be half as old as his father. How old is the daughter now?

There are 2 people near the river and both of them want to get on the other side. The boat can only take one of them. But they got across.
How?

Twenty frogs are sitting on a log floating on the surface of a river. Two of them decide to jump off into the water.

How many frogs are there on the log at this moment?

There is a family that live in a round house. The two parents go out for a movie and leave a babysitter to watch their son. They come back and the kid was not there. Some one kidnapped him. The maid said she was cleaning in a corner. The cook said he was making pizza. The babysitter said she was getting a board game. Who kidnapped him.

A couple went on a climbing trip. But only the husband returned from the vacation and said that his wife slipped off while climbing and died. On investigating, the local sheriff arrested him saying, 'Your travel agent called. You murdered your wife.'

The man did not inform anyone about the trip. Then how was the agent so sure that it was a murder?

My friends called me Iron59 because my parents are a chemist and a mathematician. What is my real name?

Who is that with a neck and no head, two arms and no hands? What is it?

A man dies of old age on his 25 birthday. How is this possible?

No one wants to have it, but if one got it, he does not want to lose it. What is It?