## Click here to go to the IXL website for all kinds of 8th grade topics and review problems.

# REAL NUMBERS

In this unit we went over Real Numbers and the classification system that is set up with Real Numbers. Here is the Rational Numbers Poster we created in class

We used Nesting boxes to demonstrate how the sub groups are inside each other.

**Click here to do IDENTIFY REAL NUMBERS online and get automatic feedback (it grades it)! 🙂**

# Ordering Numbers

Watch a video about ordering number here!

To order numbers there are a couple steps to follow.

1st: Convert all you numbers to decimals

2nd: Convert these to percents

3rd: Label a number line

4th: Put your numbers on the number line

## Ascending versus Descending

## Ascending Order

To put numbers in order, place them from lowest (first) to highest (last).

This is called “Ascending Order”.

Example: Place 17, 5, 9 and 8 in **ascending** order.

- Answer: 5, 8, 9, 17

## Descending Order

Sometimes you want the numbers to go the other way, from highest down to lowest, this is called “Descending Order”.

Example: Place 17, 5, 9 and 8 in **descending** order.

- Answer: 17, 9, 8, 5

**Click here or here or here or here or here to practice Ordering Numbers online and get automatic feedback (it grades it)! 🙂**

**Scientific Notation**

Scientific notation is about writing really big and really small numbers in an equivalent form.

We normally write numbers in what we call STANDARD NOTATION, but we can also write this number in SCIENTIFIC NOTATION.

For example the number three hundred and twenty.

**STANDARD: 320**

**SCIENTIFIC NOTATION: 3.2 × 10 ^{2}**

## CONVERTING NUMBERS

When given a number in scientific notation you can easily convert the number to standard notation.

**Example #1**

**Convert from Scientific Notation: 3.6 × 10 ^{12 }**

**to Standard Notation**

Now, since the **exponent** on 10 is **positive**, I know they are looking for a * LARGE *number, so I’ll need to move the decimal point in the

**positive direction**(to the right), in order to make the number LARGER. Since the exponent on 10 is “

**12**“, I’ll need to move the decimal point

**twelve places**over.

First, I’ll move the decimal point twelve places over. I make little loops when I count off the places, to keep track:

Then I fill in the loops with zeroes:

In other words, the number is **3,600,000,000,000**, or 3.6 trillion

**Example #2**

**Convert 4.2 × 10 ^{–7} to standard notation.**

Since the **exponent** on 10 is **negative**, I am looking for a * small *number. Since the

**exponent**is a

**seven**, I will be moving the decimal point

**seven places**. Since I need to move the point to get a

**number, I’ll be moving it to the**

*small***left**. The answer is

**0.00000042**