using four eights (8) and a one (1) and one mathematical symbol , create the number 100

Can you replace the X (both small and big x) with the numbers between 1 to 19 such that all the rows of 3 numbers between X (big x) sum to 23?

Only one color, but not one size,
Stuck at the bottom, yet easily flies.
Present in sun, but not in rain,
Doing no harm, and feeling no pain.
What is it?

It is a nine-letter word.
The exact opposite of the phrase "friendly and outgoing"
It contains the word "over".
It starts will a vowel.

What is it?

Why is the longest human nose just 11 inches?

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

I am Huge on Sunday and Saturday.
I am small from Tuesday to Thursday.
I do not exist on Monday and Friday.
Who am I?

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

What is the next number in the series?

15 29 56 108 208 ?

When is the top of a mountain similar to a savings account?