Section 0.1

1 / 10

# Section 0.1 - PowerPoint PPT Presentation

Section 0.1. Rational Numbers, Rounding, and Order of Operations. Rational Numbers. Rational Numbers are any numbers that can be written as a fraction. That means: Integers Fractions Decimals. Here are some examples: 5, 1/3, -5.1234, -15 Here are some non-examples: , , 3.1245789….

I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.

## PowerPoint Slideshow about 'Section 0.1' - nerita

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript

### Section 0.1

Rational Numbers, Rounding, and Order of Operations

Rational Numbers
• Rational Numbers are any numbers that can be written as a fraction.
• That means:
• Integers
• Fractions
• Decimals

Here are some examples:

5, 1/3, -5.1234, -15

Here are some non-examples:

, , 3.1245789…..

Rational Numbers
• Classify the following numbers as rational or irrational.

-3, 0, , , , 7.51, , -, 6.666666

Solution:

Rational Numbers

-3, 0, , 7.51, , -, 6.666666

Irrational Numbers

- this is a non repeating , non terminating decimal.

– this is always irrational

Rounding and Truncation
• Rounding – Look to the right of the specified decimal place. If the number is 5 or greater, round up one. If the number is 4 or less, leave it alone. (You know this. You have been doing it forever!!!)

Round 7.356894 to 3 decimal places.

7.356894 look at the number to the right of the 6

it is higher than 5 so round up.

7.357

Rounding and Truncation
• Truncation – Cutoff what you don’t want.

Approximate 7.456892 to 3 decimal places by truncation

7.456892 Cutoff everything past the “6”

7.456

Rounding and Truncation
• Approximate 17.368204 to two decimal places by

A) Rounding B) Truncation

• Approximate 23.02492 to two decimal places by

A) Rounding B) Truncation

Solution:

1. A) 17.37 B) 17.36 2. A) 23.02 B) 23.02

Order of Operations
• You know this: PEMDAS
• Parentheses
• Exponents
• Multiplication
• Division
• Subtraction
• Work left to right.
• If you see division before multiplication, that is okay do it first. Multiplication/division and addition/subtraction are done at the same time.
Order of operations
• Example 1

7 – 2 * 5 + 4 * 3 – 5 No parentheses or exponents, so look for multiplication/division 1st.

7 – 10 + 12 – 5 Go back to the beginning to do addition/subtraction.

-3 + 12 – 5

9 – 5

4

Order of Operations
• Example 2

-3(x – y) + 4(3x – 2y) Here there are parentheses, but you cannot combine anything. You need to distribute 1st.

-3x + 3y + 12x - 8y Now combine like terms

9x – 5y

Order of operations
• Try a few on your own. Ask a partner if they are right, before I show you the answers.

1. 8 * 5 - 4 + 6 ÷ 2 2. -2(5 + 3) + 7(3 – 2 * 5)

3. 3(5x – 2y) – 7(x – 3y) 4. 6x(5 + 2 - 4) – (3 * 2 ÷ 3)

Solutions:

1. 39 2. -65 3. 8x + 15y 4. 18x - 2