Translate a real-world written description into an algebraic inequality in the form of x > a, x < a, x ≥ a or x ≤ a. Represent the inequality on a number line.
Examples
Mrs. Anna told her class that they will get a pizza if the class has an average of at least 83 out of 100 correct questions on the semester exam. The inequality g ≥ 83 can be used to represent the situation where students receive a pizza and the inequality g < 83 can be used to represent the situation where students do not receive a pizza.
Clarifications
Clarification 1: Variables may be on the left or right side of the inequality symbol.Benchmark Instructional Guide
Connecting Benchmarks/Horizontal Alignment
Terms from the K-12 Glossary
- Number Line
Vertical Alignment
Previous Benchmarks
Next Benchmarks
Purpose and Instructional Strategies
In grade 5, students plotted, ordered and compared multi-digit decimal numbers up to the thousandths using the greater than, less than, or equal to symbols. Students translated written real-world and mathematical situations into numerical expressions. In grade 6, students plot, order and compare on both sides of zero on the number line with all forms of rational numbers. The algebraic inequalities include “is less than or equal to” (≤) and “is greater than or equal to” (≥). In grade 7, students will write and solve one-step inequalities in one variable and represent the solutions both algebraically and graphically.- Instruction emphasizes the understanding of defining an algebraic inequality both numerically and graphically. Students should explore how “is greater than or equal to” and “is strictly greater than” are similar and different as well as “is less than or equal to” and “is strictly less than.” Students should use appropriate language when describing the algebraic inequality.
- The expectation of this benchmark includes translating from an algebraic inequality into a real-world written description.
- As students identify and write the inequality relationships it is important to ask students about other values on the number line (MTR.6.1, MTR.7.1).
- For example, when representing the inequality > 1 on the number line, students should compare numbers to 1 in order to determine whether to shade to the left or to the right of 1.
- Instruction includes inequalities where the variable is on the left and right side of the inequality symbol. This will create flexibility in their thinking to be able to apply in future applications of inequalities. Students should form equivalent statements to demonstrate their understanding of how inequalities are related. Students should use context to determine which situation is most appropriate for forming the inequality (MTR.2.1).
- For example, > 8 can be written as 8 < .
- Students should understand the solution set and its graphical representation on a number line. This includes showcasing inclusive (closed circle) or non-inclusive (open circle) as well as shading to represent the solution set.
- A number line is a useful tool for modeling inequality situations.
- For example, students can model on a vertical number line having to be at least 40 inches tall to ride a roller coaster.
- Instruction includes the understanding how inequality relationships can be represented in real-world contexts from the beginning. It can be talked about in terms of character lives in a video game, or amount of money to purchase apps or popular items. Allow students opportunities to identify their own inequality relationships as written descriptions and share with classmates to have them create the algebraic inequality and represent it on the number line (MTR.1.1, MTR.4.1, MTR.5.1, MTR.7.1).
Common Misconceptions or Errors
- Students may incorrectly think that the variable must always be written on the left-hand side of the inequality symbol. It is important that students be able to read and understand the context regardless of the side of the inequality that the variable is placed.
- Students may incorrectly shade the solution set of an inequality on a number line. Using verbal descriptions acknowledging the relationship between the number and the variable can support students in identifying the solution set. Students should test numbers on each side of the value to determine if they are true statements.
- For example, if the relationship is > 3, have students replace the with −5 and 5 to see which one creates a true statement.
- Students may not understand the difference between inclusive and non-inclusive solutions sets on a number line. Students can benefit from reasoning within a real-world context.
Strategies to Support Tiered Instruction
- Teacher provides inequalities with variables on the left or right side of the symbol and has students write two verbal comparisons for each statement.
- For example, >15 can be read as “ is greater than 15” or as “15 is less than .”
- For example, ≤ 6 can be read as “ is less than or equal to 6” or as “6 is greater than or equal to .”
- Instruction includes the use of substitution to test various numbers to determine which set of numbers will make true statements and then to draw a ray in the appropriate direction. The same strategy holds true for reasoning with inclusive and non-inclusive solution sets and the difference in the solid or open point at the indicated value.
- Teacher provides students with flash cards to practice and reinforce academic vocabulary.
- Instruction includes creating a list of common terms from contextual situations that may be used to describe situations requiring an inequality symbol and add to as an interactive anchor chart as additional situations arise.
- Examples include the table below.
- Examples include the table below.
- Teacher uses verbal descriptions to acknowledge the relationship between the number and the variable to support students in identifying the solution set. Students should test numbers on each side of the value to determine if they are true statements.
- For example, if the relationship is > 3, have students replace the with −5 and 5 to see which one creates a true statement.
Instructional Tasks
Instructional Task 1 (MTR.4.1)
- The graph below describes the altitudes, measured in feet, at which civilian aircraft must provide everyone with supplemental oxygen, according to the U.S. Federal Aviation Regulation.
- Determine an inequality to represent the situation. How can this be written in another way?
Instructional Task 2 (MTR.4.1)
According to historical records, the highest price for regular gas in Florida over the last ten years was just under $4.06. Tammy states that this is an inclusive relationship. Christine says it is a non-inclusive relationship. Who is correct and why?
Instructional Items
Instructional Item 1
Graph x > 3 on a number line.Instructional Item 2
According to Interstate Highway Standards, U.S. and state highway traffic lanes must be at least 12 feet wide. Write an inequality to represent the widths that traffic lanes can be.Instructional Item 3
Trini is allowed to play video games no more than 4 hours over the weekend. Graph the inequality on a number line.Instructional Item 4
A farmer is going to plant more than 50 acres in corn this year. If a represents the number of acres planted in corn, write an inequality to describe all possible values of a.Instructional Item 5
High altitude parachute jumps are usually made from an altitude that is no more than 35,000 feet to avoid frostbite from extreme cold. If h represents the height of a jumper, write an inequality to describe all possible values of h.*The strategies, tasks and items included in the B1G-M are examples and should not be considered comprehensive.
Related Courses
Related Access Points
Related Resources
Formative Assessments
Lesson Plans
Original Student Tutorials
Perspectives Video: Expert
Text Resources
Tutorial
MFAS Formative Assessments
Students are given an inequality to graph and asked to select sample solutions.
Students are given an inequality to graph and asked to list sample solutions.
Original Student Tutorials Mathematics - Grades 6-8
Follow Jamal as he translates theme park written descriptions into algebraic inequalities in this interactive tutorial.
Follow Jamal as he represents algebraic inequalities on a number line while visiting a theme park with his family in this interactive tutorial.
This is part 2 in a two-part series on inequalities. Click HERE to open part 1.
Computer Science Original Student Tutorials
Explore computer coding on the farm by using relational operators and IF statements to evaluate expressions. In this interactive tutorial, you'll also solve problems involving inequalities.
Click below to check out the other tutorials in the series.
Explore computer coding on the farm by using IF statements and repeat loops to evaluate mathematical expressions. In this interactive tutorial, you'll also solve problems involving inequalities.
Click below to check out the other tutorials in the series.
Student Resources
Original Student Tutorials
Follow Jamal as he represents algebraic inequalities on a number line while visiting a theme park with his family in this interactive tutorial.
This is part 2 in a two-part series on inequalities. Click HERE to open part 1.
Type: Original Student Tutorial
Explore computer coding on the farm by using IF statements and repeat loops to evaluate mathematical expressions. In this interactive tutorial, you'll also solve problems involving inequalities.
Click below to check out the other tutorials in the series.
- MacCoder’s Farm Part 1: Declare Variables
- MacCoder’s Farm Part 2: Condition Statements
- MacCoder's Farm Part 3: IF Statements
Type: Original Student Tutorial
Explore computer coding on the farm by using relational operators and IF statements to evaluate expressions. In this interactive tutorial, you'll also solve problems involving inequalities.
Click below to check out the other tutorials in the series.
- MacCoder’s Farm Part 1: Declare Variables
- MacCoder's Farm Part 2: Condition Statements
- MacCoder's Farm Part 4: Repeat Loops
Type: Original Student Tutorial
Follow Jamal as he translates theme park written descriptions into algebraic inequalities in this interactive tutorial.
Type: Original Student Tutorial
Tutorial
Learn how to write inequalities to model real-world situations.
Type: Tutorial