Before you can register, you must answer 5 simple questions. All answers are numbers. If the answer is integer, simply type it in the corresponding field. A fraction must be typed in its simple irreducible form, i.e. 5/2 (neither 2.5, nor 2 1/2).

An office has 30 people. They must choose the manager and the assistant manager. In how many ways can this be done?

How many diagonals does a convex 30-gon have?

What is next: 1 4 9 16 25 ...?

How many distinct natural divisors does the number 90 have?

A brick weighs 1 Kg and half a brick. How much does the brick weigh?