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

There are five vowels (a, e, i, o, u) in the English language.
Can you tell us a word that contains all these vowels?

No matter how little or how much you use me, you change me every month. What am I?

What question can you never answer yes to?

2, 3, 5, 9, 17, _ What is the next number in the sequence?

There are 2 cops parked along a one-way street looking for traffic violations. They spot a taxi driver going in the wrong direction, yet they do nothing.

Why?

Remove two matchsticks to make the below equation correct.

Name one eight-letter word with 'kst' in the middle, 'in' the beginning, 'and' at the end.?

You are given with the following sum. Each of the letters can be decoded as a digit. If we tell you that D = 5, then can you solve it entirely?

DONALD
+GERALD
=ROBERT

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 ()