What is harder to catch the faster you run?

How can you drop a raw egg from a height onto a concrete floor without cracking it?

How can a man go eight days without sleep?

Which tank will fill first?

How many words can a pen with half refill write?

If you say my name, I will no longer exist. What am I?

What is the next number in this series?

4,12,84,3612....

Use the digits from 1 up to 9 and make 100.

Follow the rules.
=> Each digit should be used only once.
=> You can only use addition.
=> For making a number, two single digits can be combined (for example, 4 and 2 can be combined to form 42 or 24)
=> A fraction can also be made by combining the two single digits (for example, 4 and 2 can be combined to form 4/2 or 2/4)

Question: how can we do this?

Today is John's birthday.
A year ago, John had five candles and he lit all the candles except the one at the last.
Now he is going to light all the candles.

How old is John Today?

(He is not five today.....)

Can you replace the question mark with the correct number?