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Equations and Mental Math. Standard: AF 1.1 Write and solve one-step linear equations in one variable.
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Equations and Mental Math • Standard: AF 1.1 Write and solve one-step linear equations in one variable. • Objective: Students will use mental math to write and solve one-step linear equations in one variable by performing inverse operations, identifying missing quantities, using graphic organizers, writing reflective summaries, and scoring an 80% proficiency on exit slip quizzes and online assessments.
Key Words • Expression • Equation • Variable • Inverse Operations
SOLUTION a. n + 5 = 14 Write equation. ? 9 + 5 14 Substitute 9 for n. = 14 = 14 14=14, so 9 is a solution. Example 1 Checking Possible Solutions Tell whether the number is a solution of . n + 5 = 14 a. 9
SOLUTION b. n + 5 = 14 Write equation. ? + 7 5 14 Substitute 7 for n. = 12 = 14 12=14, so 7 is a not a solution. Example 1 Checking Possible Solutions Tell whether the number is a solution of . n + 5 = 14 b. 7
Verbal sentence Equation The difference of twice a number and 3 equals 4. a. – 4 2y – 3 = – 9y = 36 b. The product of 9 and a number is 36. c. –3 is equal to twice the sum of a number and 2. –3 = ( ) 2 y + 2 Example 2 Translating Verbal Sentences
3 9 + 3 = 12 b. n – 5 = 10 What number minus 5 equals 10? 15 15 – 5 = 10 c. 4t = 20 Four times what number equals 20? 5 4(5) = 20 Example 3 Using Mental Math to Solve Equations Equation Question Solution Check a. 9 + x = 12 Nine plus what number equals 12?
36 36 = 12 3 Example 3 Using Mental Math to Solve Equations Equation Question Solution Check m d. = 12 What number divided by 3 equals 12? 3
solution ANSWER not a solution 2. 7 = 13 – n; 5 ANSWER 6 solution ANSWER 3. = 3; 2 y Write as an equation: The difference of 5 and twice a number is 17. 4. 5 – 2n = 17 ANSWER Guided Practice for Examples 1, 2, and 3 Tell whether the number is a solution of the equation. 1. 3x = 12; 4
5. 7x = 35 5 ANSWER 6. 15 = m – 6 21 ANSWER 20 4 ANSWER ANSWER 7. 12 + a = 32 24 8. = 6 n Guided Practice for Examples 1, 2, and 3 Solve the equation using mental math.