Can you solve this amazing hard number series problem?
7, 8, 10, 12, 16, 18 ?

Take one out and scratch my head, I am now black but once was red. What am I?

Using four sevens (7) and a one (1) create the number 100. Except for the five numerals, you can use the usual mathematical operations (+, -, x, :), root and brackets ()

There is an English word that can be used up to four times in a row without modifying the spelling and form a valid grammatical sentence.

Do you know what word is that?

What country can make you shiver?

Consider this: Arnold Schwarzenegger has a big one. Michael J. Fox has a small one. Prince doesn’t have one. The Pope has one but never uses it. Bill Clinton has one and uses it all the time. What is it?

Look at the below sequence of letters and tell us what the next letter should be:

O T T F F S S ?

You may enter, but you may not come in. I have space, but no room. I have keys, but open no lock. What am I?

What number comes next in the series?

5 15 5 18 5 24 14 20 _

I am the beginning of the end, and the end of time and space. I am essential to creation, and I surround every place. What am I?