1. Lesson 2 Compare and Order Rational Numbers

2. Lesson 2: Compare and Order Rational Numbers
Objective: SWBAT compare and order rational numbers. Do Now: Worksheet # 1 - 6

3. Lesson 2: Compare and Order Rational Numbers
Definitions
Rational Number is a number that can be
expressed as a ratio of two integers.
Common denominator is a common multiple of
the denominators of two or more fractions.
Least Common Denominator is the least common
multiple of the denominators.

5. Natural Numbers – 1, 2, 3, 4, ……. Whole Numbers – 0, 1, 2, 3, 4, ……
Natural Numbers – 1, 2, 3, 4, …….. Whole Numbers – 0, 1, 2, 3, 4, …….. Integers - ……-4, -3, -2, -1, 0, 1, 2, 3, 4, …….. Rational Numbers – any number that can be written as a ratio, a/b Irrational Numbers – any number that is not a rational number ≠ a/b Real Numbers – all the rational and irrational numbers

6. Lesson 2: Compare and Order Rational Numbers
Write the numbers from the list in the proper section of the Venn Diagram. ∏
.2222…… -1/2 % 5
1 2 3

7. Lesson 2: Compare and Order Rational Numbers
To compare rational numbers use symbols:
< (less than)
> (greater than)
= (equal)
You can compare rational numbers in decimal or fraction form.
When comparing rational numbers in decimal form:
Compare by place value (left to right)
< 0.25
> 0.4
< -1.2 -

8. Lesson 2: Compare and Order Rational Numbers
When comparing rational numbers a number line can be helpful.
Graph the numbers on a number line
The number to the left is less than the number to the
right (use the < symbol)
The number to the right is greater than the number to
the left (use the > symbol)
Compare ____ -1 -2 -1 1 2

9. Lesson 2: Compare and Order Rational Numbers
You can also compare numerators.
____ -1
- ____ - change to improper fraction
< compare numerators
< -1

10. Lesson 2: Compare and Order Rational Numbers
When comparing rational numbers with different denominators.
Find the LCD (least common denominator)
Change each fraction to equivalent fractions using the LCD
Compare the numerators
Compare ____
LCD is X X 2
X X 2
> then >

11. Lesson 2: Compare and Order Rational Numbers
** You can find a common denominator just by
multiplying the two denominators
How to find the LCD
List multiples of the largest denominator and
see if the other denominator is a factor
Example: 1 2
is the larger
10: 10, 20, 30, 40 8 is a factor of 40
LCD is 40
Try It! 12 and 30

12. Lesson 2: Compare and Order Rational Numbers
- Find the GCF and divide it into either number
- Multiply the quotient to the other number
Example: 1 2
is the GCF
10/2 = 5 5 x 8 = 40
LCD is Try It! 12 and 30

13. Lesson 2: Compare and Order Rational Numbers
- Find a factor of both numbers until the only
factor is 1
- Multiply all factors to remaining numbers
Example: 1 2
10 8
2 x 1 x 5 x 4 = 40 Try It! 12 and 30

14. Lesson 2: Compare and Order Rational Numbers
4. Use Prime Factorization method x 5 2 x 4 multiply 2 x 2 the most of each LCD: 2 x 2 x 2 x 5 = 40 prime number Try It! 12 and 30

15. Lesson 2: Compare and Order Rational Numbers
Try It!

16. Lesson 2: Compare and Order Rational Numbers
When ordering rational numbers:
change number to decimal
line up by decimal point and compare by place value
Order the set {3.44, , 3.14, } least to greatest rd
… 2nd st
… 4th
Answer: 3.14, , 3.44,

17. Lesson 2: Compare and Order Rational Numbers
Try It!
{23%, 0.21, , }
{7.49, , 7.5%}
{-1.4, , -1.25}

18. Classwork Guided Practice #1-5 Independent Practice #1-10
Problem Solving Practice #1 - 8

19. Closure
Question: What is the easiest way to compare rational numbers? Exit Ticket Homework: Practice # 1-25

20. Exit Ticket Compare <, >, or =. 3 5 8 6 .2 20%
3 5
8 6
.2 20%
Order least to greatest.
3. {0.43, 4%, .4, 4.1}

21. Homework