How do you go from 98 to 720 using just one letter?

This puzzle is for Harry Potter fans. Do you know why Tom Riddle is called Lord Voldemort?

Why do Chinese men eat more rice than Japanese men do ?

On a bright sunny day, two fathers took their son fishing in the lake. Each man and son were able to catch one fish. When they returned to their camp, there were only three fishes in the basket. What happened?

PS: None of the fish were eaten, lost, or thrown back.

Find the number of squares in the below-given picture.

If I remove one from eleven it becomes Ten and if I remove one from nine also becomes Ten. How?

I am a five-letter word under you,
Remove the first letter and I am above you,
Remove the second as well and I am around you.

Who am I?

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

Can you make a fire with just a single stick?

Four people need to cross a rickety bridge at night. Unfortunately, they have only one torch and the bridge is too dangerous to cross without one. The bridge is only strong enough to support two people at a time. Not all people take the same time to cross the bridge. Times for each person: 1 min, 2 mins, 7 mins and 10 mins. What is the shortest time needed for all four of them to cross the bridge?