# Category: General

## Top 10 Popular Math Problems in 2016-2017

It’s been a year since I started this math blog!!

More than 500 problems were posted during a year (July 19th 2016-July 19th 2017).

I made a list of the 10 math problems on this blog that have the most views.

Can you solve all of them?

The level of difficulty among the top 10 problems.
【★★★】 Difficult (Final Exam Level)
【★★☆】 Standard(Midterm Exam Level)
【★☆☆】 Easy (Homework Level)

## Problem 496

Prove that if $2^n-1$ is a Mersenne prime number, then
$N=2^{n-1}(2^n-1)$ is a perfect number.

On the other hand, prove that every even perfect number $N$ can be written as $N=2^{n-1}(2^n-1)$ for some Mersenne prime number $2^n-1$.

## Problem 446

Prove that there are infinitely many prime numbers in ONE-LINE.

## Beautiful Formulas for pi=3.14…

The number $\pi$ is defined a s the ratio of a circle’s circumference $C$ to its diameter $d$:
$\pi=\frac{C}{d}.$

$\pi$ in decimal starts with 3.14… and never end.

I will show you several beautiful formulas for $\pi$.

## Mathematics About the Number 2017

Happy New Year 2017!!

Here is the list of mathematical facts about the number 2017 that you can brag about to your friends or family as a math geek.

## Problem 90

Find the largest prime number less than one million.