Use only one mathematical symbol and all numbers (0-9) to get a sum of 99

What can run but never walks, has a mouth but never talks, has a head but never weeps, has a bed but never sleeps?

When I get multiplied by any number, the sum of the figures in the product is always me. What am I?

Can you make four (4) nines (9) equal 100?

Akbar called Birbal and asked him to draw a line on the floor. He asked Birbal to make that line smaller without erasing it. Birbal smiled and did it before Akbar could blink his eyes.

How did he managed to do it?

In a guessing game, five friends had to guess the exact numbers of apples in a covered basket.
Friends guessed 22, 24, 29, 33, and 38, but none of the guesses was correct. The guesses were off by 1, 8, 6, 3, and 8 (in random order).

Can you determine the number of apples in a basket from this information?

I am taken from a mine and shut up in a wooden case, from which I am never released, and yet I am used by almost every person. What am I?

Given below is simple addition with a defined pattern pattern:
7 + 7 = 2
8 + 8 = 4
8 + 5 = 1
6 + 9 = 3
10 + 11 = 9

Can you analyze the pattern and find out the answer for:

4 + 9 = ?

If it took eight men ten hours to build a wall, how long would it take four men to build it?

What has a bottom at the top?