In this activity, students remember what the distributive property is all about before they will be expected to use it in the process of solving equations of the form p(x+q)=r later in this unit. If this activity indicates that students remember little of the distributive property from grade 6, heavier interventions may be needed.
Look for students who:
In order to explain how they know each selected expression is equivalent, students need to attend to precision in the language used (MP6).
Ask students to think of anything they know about equivalent expressions. Ask if they can:
Arrange students in groups of 2. Give 3 minutes of quiet work time and then invite students to share their responses with their partner, followed by a whole-class discussion.
Select all the expressions that are equivalent to 7(2−3n). Explain how you know each expression you select is equivalent.
14−21n is equivalent because of the distributive property. (2−3n)⋅7 is equivalent because multiplication is commutative.
The purpose of this discussion is to revisit ways of telling whether two expressions are equivalent, and to recall the distributive property.
Select a student who tested values to explain how they know two expressions are not equivalent. For example, 9−10n is not equivalent to 7(2−3n), because if we use 0 in place of n, 9−10⋅0 is 9 but 7(2−3⋅n) is 14. If no one brings this up, demonstrate an example.
Select a student who used the term “distributive property” to explain why 7(2−3n) is equivalent to 14−21n and ask them to explain what they mean by that term. In general, an expression of the form a(b+c) is equivalent to ab+ac.
All skills for this lesson
No KCs tagged for this lesson
In this activity, students remember what the distributive property is all about before they will be expected to use it in the process of solving equations of the form p(x+q)=r later in this unit. If this activity indicates that students remember little of the distributive property from grade 6, heavier interventions may be needed.
Look for students who:
In order to explain how they know each selected expression is equivalent, students need to attend to precision in the language used (MP6).
Ask students to think of anything they know about equivalent expressions. Ask if they can:
Arrange students in groups of 2. Give 3 minutes of quiet work time and then invite students to share their responses with their partner, followed by a whole-class discussion.
Select all the expressions that are equivalent to 7(2−3n). Explain how you know each expression you select is equivalent.
14−21n is equivalent because of the distributive property. (2−3n)⋅7 is equivalent because multiplication is commutative.
The purpose of this discussion is to revisit ways of telling whether two expressions are equivalent, and to recall the distributive property.
Select a student who tested values to explain how they know two expressions are not equivalent. For example, 9−10n is not equivalent to 7(2−3n), because if we use 0 in place of n, 9−10⋅0 is 9 but 7(2−3⋅n) is 14. If no one brings this up, demonstrate an example.
Select a student who used the term “distributive property” to explain why 7(2−3n) is equivalent to 14−21n and ask them to explain what they mean by that term. In general, an expression of the form a(b+c) is equivalent to ab+ac.