A. Rational Numbers Math 9

Outcomes  N9.2 N9.2  Demonstrate understanding of rational numbers including:  comparing and ordering  relating to other types of numbers  solving situational questions.

Big Ideas  Rational numbers are fractions! Most real life measurements use fractions/decimals!

Key Ideas

1. What is a Rational Number?  N9.2 N9.2  Demonstrate understanding of rational numbers including:  comparing and ordering  relating to other types of numbers  solving situational questions.

1. What is a Rational Number?

 When in decimal form how you can tell if a number is rational is if the decimal terminates or repeats.  Ex Terminates  Ex ….. Or 4.6

 When looking at a decimal if the decimal does not repeat or terminate then it is irrational.  Ex  Ex

Example 1

Example 2

Example 3

Example 4

Practice  Ex. 3.1 (p.100)  #1-8,10,11,12 oie, 13, 14 oie, oie, 21, 22, oie  Or  #3-8,10,11,12 oie, 13, 14 oie, oie, 21, 22, oie, 26, 27

2. Adding Rational Numbers  N9.2 N9.2  Demonstrate understanding of rational numbers including:  comparing and ordering  relating to other types of numbers  solving situational questions.

 Remember that you only add the numerators and the denominators stay the same.

Example 1

 To ADD decimals:  Line up the decimal points and add the columns from right to left.  Place a decimal point in the answer directly below the other decimal points.

Example 2

Example 3

Practice  Ex. 3.2 (p.111)  #1-15 oie, 17,18  Or  #3,4,7, 9-11 oie, 12-22

3. Subtracting Rational Numbers  N9.2 N9.2  Demonstrate understanding of rational numbers including:  comparing and ordering  relating to other types of numbers  solving situational questions.

 Remember just like adding rational numbers you need a common denominator and you only subtract the numerators and the denominators stay the same.

Example 1

 To Subtract:  Line up the decimal points.  Subtract the columns from right to left, regrouping if necessary.  Place a decimal point in the answer directly below the other decimal points.

Example 2

Example 3

Practice  Ex. 3.3 (p.119)  #1-14 oie  Or  #4-17 oie

4. Multiplying Rational Numbers  N9.2 N9.2  Demonstrate understanding of rational numbers including:  comparing and ordering  relating to other types of numbers  solving situational questions.

Example 1

Example 2

Example 3

Practice  Ex. 3.4 (p.127)  #1-14  Or  #5-18

5. Dividing Rational Numbers  N9.2 N9.2  Demonstrate understanding of rational numbers including:  comparing and ordering  relating to other types of numbers  solving situational questions.

 In order to divide rational numbers we have to take the reciprocal of the divisor then multiply instead of divide.

Example 1

 To divide decimals we can use long division just like to we would if we had integers.  We just have to remember to put the decimal in the place of the dividend.

Example 2

Example 3

Practice  Ex. 3.5 (p.134)  #1-13, 17,18  Or  #6-21

6. Order of Operations with Rationals  N9.2 N9.2  Demonstrate understanding of rational numbers including:  comparing and ordering  relating to other types of numbers  solving situational questions.

 BEDMAS 1.Brackets 2.Exponents 3.Division and multiplication (work left to right) 4.Adding and Subtracting (work left to right)

Example 1

Example 2

Example 3

Practice  Ex. 3.6 (p.140)  #1-17 oie  Or  #6-21 oie