Transcript Section 6.1 - prealgebraclass

BELL WORK
0011 0010 1010 1101 0001 0100 1011
• Which is larger?
• 4 or 1 0 ÷ 2
• A mouse or an elephant
• 2x3 or 3x4
• Basketball or a golf ball
1
2
4
Section 6.1
Inequalities
0011 0010 1010 1101 0001 0100 1011
April 1, 2010
1
2
4
What Will We Learn Today?
0011 0010 1010 1101 0001 0100 1011
• How to write inequalities both in written
form and mathematically
• Make estimates by rounding whole numbers
1
2
4
Which person is smaller?
Mikey is smaller than John
0011 0010 1010 1101 0001 0100 1011
In math terms…
Mikey is less than John
Mikey < John
Mikey
John
1
2
4
Which guy is larger?
0011 0010 1010 1101 0001 0100 1011
Freddie is larger than Bobbie
In math terms…
1
2
Freddie is greater than Bobbie
Freddie
Freddie
Bobbie
> Bobbie
4
Using Inequality Symbols
• > or <
• 0010
These1010
symbols
are0001
used0100
to mathematically
describe which number is larger
0011
1101
1011
or smaller
• Helpful to draw a number line
-4
-3
-2
-1
0
1
2
3
4
1
2
• If one number lies to the right of a second number, on the number line,
it is greater than the number to its’ left
• EXAMPLE: 4 lies to the right of 2 on the number line because 4 is
greater than 2
4 > 2
4 is greater than 2
4
• A number is less than a given number if it lies to the left of that
number
on the
number
line.
0011 0010
1010 1101
0001
0100 1011
-1
-2
0
1
2
3
4
5
6
1
2
• 3 lies to the left of 5 on the number line because 3 is less than 5
3 < 5
3 is less than 5
4
Examples
1.
5 ? 2
0011 0010 1010 1101 0001 0100 1011
answer: 5 > 2
* 5 is grater than 2
2.
-3 ? 0
answer: -3 < 0
* -2 is less than 0
Solve the following problems with your partners..
- mathematically ( > or < )
- and in sentence
3. -7.65 ? -9.23
answer: -7.65 > -9.23
* -7.65 is greater than -9.23
4. 2 ½ ? 2 ¾
answer: 2 ½ < 2 ¾
* 2 ½ is less than 2 ¾
1
2
4
One Step Inequalities
0011 0010 1010 1101 0001 0100 1011
1.
2x ? 10 if x = 4
step 1: since x=4, substitute 4 for x in the problem
2(4) ? 10
step 2: multiply 2 by 4
8 ? 10
step 3: now you can solve inequality
8 < 10
* 8 is less than 10
1
2
4
With your partner try these…
0011 0010 1010 1101 0001 0100 1011
1. 6x
2 + 5x
6(3) > 2 + 5(3)
18 > 17
2. 3.5
?
4x
3.5 > 4(0.5)
3.5 > 2
?
if x = 3
1
* 18 is greater than 17
if x = 0.5
2
4
* 3.5 is greater than 2
Journal Time
0011 0010 1010 1101 0001 0100 1011
• Write in your journal a summary of what
you have learned today, and what is
important to remember in the future. Also,
give an example of how you might see or
use inequalities in your life.
1
• Share with us your example!
2
4
Homework
0011 0010 1010 1101 0001 0100 1011
• In text: # 3-21 odd
• Worksheet
• All Due Tomorrow
1
2
4