A. Rational NumbersMath 9

Outcomes

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

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. 2.25 Terminates

Ex. 2.333333333333….. Or 4.6

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

Ex. 2.34567534789064567555346623453345433

Ex. 5.45456456745678456789

Example 1

Example 2

Example 3

Example 4

Practice

Ex. 3.1 (p.100)

#1-8,10,11,12 oie, 13, 14 oie, 16-18 oie, 21, 22, 23-24 oie

Or

#3-8,10,11,12 oie, 13, 14 oie, 16-18 oie, 21, 22, 23-25 oie, 26, 27

2. Adding Rational Numbers

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

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

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

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

Demonstrate understanding of rational numbers including:

comparing and ordering

relating to other types of numbers

solving situational questions.

BEDMAS1. 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