## Identify and describe properties of prime, composite, square and triangular numbers(ACMNA122)

Know:

• What a number is.
• Numbers can be classified into different categories

Understand:

• That certain numbers can be classified by their properties..

Do:

I can identify prime, composite, square and triangular numbers.

Essential Questions:

• What are integers?
• When do we work with integers in the real world?
• Are there only positive numbers in the world?

## Prime Numbers

Are numbers that only can be divided by 1 and itself.

For example, 13 is a prime number because it can only be divided by 1 and 13.

These are the prime numbers under 100. ## Composite Numbers

Are numbers that have more than 2 factors. A factor is a number that can divide evenly into another number.

For example, 25 is a composite number because it can be divided evenly by 1 , 5 and 25.

These are the composite numbers under 100. ## Square Numbers

Are numbers that form perfect squares. An easy way of finding square numbers is multiplying a number by itself.

For example, 1 x 1 = 1, 2 x 2 = 4, 3 x 3 = 9, 4 x 4 = 16. These are all square numbers. ## Triangle Numbers

Are numbers that form perfect triangles.

Notice the pattern,

1
1+2 = 3
1+2+3 = 6
1+2+3+4 = 10
1+2+3+4+5 = 15 ## All the square numbers under 150. 