In this Grade 8 lesson from Big Ideas Math, Course 3 (Chapter 1), students learn to solve simple equations using the Addition, Subtraction, Multiplication, and Division Properties of Equality. The lesson also introduces inductive reasoning through triangle angle-sum exploration, where students write and apply equations to find unknown angle measures. Aligned to standards 8.EE.7a and 8.EE.7b, students practice isolating variables with integers, decimals, fractions, and expressions involving pi.
Section 1
Solving with addition and subtraction
Subtraction Property of Equality: For any numbers , , and , if , then .
Addition Property of Equality: For any numbers , , and , if , then .
Use these properties to isolate the variable by performing the inverse operation on both sides of the equation.
Section 2
Solving with multiplication and division
The Division Property of Equality: For any numbers , , and , and , if , then .
The Multiplication Property of Equality: For any numbers , , and , if , then .
Use these properties to isolate the variable by performing the inverse operation on both sides of the equation.
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Section 1
Solving with addition and subtraction
Subtraction Property of Equality: For any numbers , , and , if , then .
Addition Property of Equality: For any numbers , , and , if , then .
Use these properties to isolate the variable by performing the inverse operation on both sides of the equation.
Section 2
Solving with multiplication and division
The Division Property of Equality: For any numbers , , and , and , if , then .
The Multiplication Property of Equality: For any numbers , , and , if , then .
Use these properties to isolate the variable by performing the inverse operation on both sides of the equation.
Book overview
Jump across lessons in the current chapter without opening the full course modal.
Continue this chapter