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!

### Math for Early Age /Elementary (G5 under), Numbers

# Sample Review Quiz for Grade 3 /4

A sample quiz questions for Grade 3/4.

Topics covered: Numbers of 1,000 – 10,000; Addition with Carry; Place Values; Time and Clock; Pattern Rules in Number Sequence.

Reference Purpose only — do not copy.

### 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!

### Functions, High School Math, Trigonometry

# Isn’t that cool? Finding Angle(s) on a Calculator Without Trig Functions

Tells you a tip on how to find the angles (in degrees) of any right triangle given the three sides — using a calculator WITHOUT trig functions. Simple formula presented — pretty cool!

### Geometry, Junior Math (Gr 6 - 9), Numbers

# How Many Isosceles Triangles Are in a Pentagon – Pentagram?

.Surely you’ve discovered that the figure below is clipped from a pentagon. Right? Yeh! let us focus within the border drawn with a crayon, that is, within triangle DAB. How many isosceles are there within it? (For the moment, ignore the smaller pentagram A’C’E’B’D’ and all the triangle formed by their intersections.) Let’s count it!…

### Geometry, Junior Math (Gr 6 - 9), Math BASICS

# Protected: Regular Polygons and Perfect Circles – Defs & Principles

There is no excerpt because this is a protected post.

### Junior Math (Gr 6 - 9), Skills in Math Contests

# Sample Questions for Gauss Contests

Gauss contests are very popular math contest in Canada, for grade 7-8 students. Questions range from pretty easy to somewhat challenging.

The sample questions chosen here are on the challenging sides.

You can try your talent on these questions!

### Geometry, Math BASICS, Numbers

# Protected: The (3-4-5) Pattern for Pythagorean Triplets

There is no excerpt because this is a protected post.

### Geometry, Math BASICS, Numbers

# π Ideas (1) a Fun Way of Finding the π Value

#### This describes a fun way to find the π value.

It does not use any area calculation. Not even directly apply the Pythagorean Theorem. Basically it uses *the radius* as a *unit* to measure *the circumference* along the circle. But how can you measure a curve using a line segment, without getting into tech difficulties? There’s simple yet smart solutions. Read on, you can find that out!

### Geometry, High School Math, Methods of Learning

# Protected: Circular Geometry and Thales’ Theorem

There is no excerpt because this is a protected post.