A brief discussion about the concept of primes. Also included are some prime-sense: what are the possible last digit of a prime number? How many primes are in the first hundred natural numbers? etc.

There are more amazing stuffs!

# Algebra

Expression in letters representing numbers. A basic yet powerful tool in math.

### Algebra, Numbers

# A surprising expression for π

This article is about a very neat expression that evaluates to the value of π.

It is amazingly surprising!

### Algebra, Equations and Inequalities, Glossary, Math BASICS

# Def: Unknowns

An unknown is an quantity we do not know yet.

In algebra, an unknown is represented by a letter. We will later find the value of unknown from the given conditions (this is called “solving for unknown”).

### Algebra, Junior Math (Gr 6 - 9), Methods of Learning, Numbers

# A Magic-square Like Puzzle, with Usual and Shortcut Solutions

Once we understood a math problem, and mastered relevant methods, we can find many different ways to solve the problem. That is, there are many shortcuts.

### Algebra, Equations and Inequalities, Junior Math (Gr 6 - 9), Math BASICS, Numbers

# Solve /Find a Number by Algebra

Word problems with numbers are a convenient facility to learn equations.