Math playground is a website where you play number games. Here, in this thread, let us make 1 website to 1 forum thread. So, solve some puzzles, and get points :

Every correct guess gives you 10 points. If wrong (unless mathgogocart's power is enabled), you get one point ONLY.

Levels :

Novice = 0 points

Apprentice = 25 points

Beginner = 75 points

Amateur = 375 points

...

When you go to particular ranks, you get powers (powers are activated only if you type them):

Apprentice = Double power - doubles your point score

Beginner = Trouble or Double ? - when you're wrong, you're considered correct

Junior (Level 5) = Tripler - triples your score

Junior III (Level 7) = Joker - if you think you can't answer the question, get this joker and get 10 points, automatically

*If you answered and want to get The Double Power / Tripler, put those powers in parentheses.

Okay, let's start.

There are 99 students in a class. There are four people that are told to answer. Their number is 4, 10, 25 and 63, respectively.

* 5 points each

I. What is the rule of the term?

II. Why is it that it is 63, not 62.5 ?