Lesson 4 Greater Than? Develop Understanding

Jump Start

Which One Doesn’t Belong? Examine each of the models below and determine which one is different from the rest. Be prepared to justify your answer.

A.
A number line with an arrow pointing to the right beginning at a closed end point at -5 –8–8–8–6–6–6–4–4–4–2–2–2222444000
B.

C.
A green rectangle approximately 5 units wide and 1 unit tall with four 1 X 1 blue squares connected in a row and attached to the right side of the green rectangle
D.
A number line with 3 arrows pointing to the right. All arrow have a closed end point. The first arrow begins at -5, arrow 2 begins at -1; arrow 3 begins at 3. –6–6–6–4–4–4–2–2–2222444666888000
Reason:

Learning Focus

Reason about inequalities.

Justify properties of inequalities.

Use inequality notation.

What are the properties of inequalities? Are they different from the properties of equations?

Open Up the Math: Launch, Explore, Discuss

Given a mathematical statement and two expressions, decide which of the two expressions is greater, if the expressions are equal, or if the relationship cannot be determined from the statement. Write an equation or inequality that shows your answer and explain why your answer is correct. Watch out—this gets tricky!

Example:

Statement:

Which is greater? or

is greater. . Because if , , , and .

1.

Statement: is an integer.

Which is greater? or

Try it yourself:

2.

Statement:

Which is greater? or

3.

Statement:

Which is greater? or

4.

Statement:

Which is greater? or

5.

Statement:

Which is greater? or

6.

Statement:

Which is greater? or

7.

Statement:

Which is greater? or

8.

Statement:

Which is greater? or

9.

Statement:

Which is greater? or

10.

Statement: and

Which is greater? or

11.

Statement:

Which is greater? or

Ready for More?

Here is one more problem that will make you dig a little deeper. See what you can do!

Statement:

Which is greater? or ?

Takeaways

Properties of Inequalities

Addition Property:

Subtraction Property:

Multiplication Property:

Division Property:

Vocabulary

Lesson Summary

In this lesson, we reasoned about inequalities to compare algebraic expressions. We found and justified the addition, subtraction, multiplication, and division properties of inequalities.

Retrieval

1.

Write an equation to fit with the story, and solve to answer the question.

Augustus has made a pile of candies, and he is giving away candies a day from this pile. When will he have candies left in this pile?

Evaluate each function for the indicated values.

2.

a.

b.

3.

a.

b.

Solve each of the literal equations for the indicated variable.

4.

Solve for .

5.

Solve for .