What mathematical symbol can be put between 5 and 9, to get a number bigger than 5 and smaller than 9?

A blonde put eyeliner on her head. Why?

In a school, there are four subjects. Seventy percent of students study English, seventy five percent of students study Science, eighty five percent of students study Mathematics and eighty percent of students study Spanish.

Can you calculate the percentage of students that study all four subjects?

The product of three consecutive numbers is 7980.
Then the sum of these consecutive numbers would be?

One absent-minded ancient philosopher forgot to wind up his only clock in the house. He had no radio, TV, telephone, internet, or any other means for telling time. So he travelled on foot to his friend's place a few miles down the straight desert road. He stayed at his friend's house for the night and when he came back home, he knew how to set his clock. How did he know?

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

There is a box full of marbles,
all but two are blue,
all but two are green,
and all but two are red.

How many marbles are in the box?

Find the combined weight of the Cat, Dog and Rabbit in the given picture.

What is the fewest number of coins that would be required in order to make sure each and every coin touches exactly three other coins?

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