subtraction equations
TRANSCRIPT
2-6 Subtraction Equations
Course 1Course 1
2-6 Subtraction Equations
Course 1
Warm UpWarm Up
Lesson PresentationLesson Presentation
Problem of the DayProblem of the Day
2-6 Subtraction Equations
Course 1
Warm UpSolve each equation.
1. x + 7 = 22
2. 18 + x = 105
3. 16 = x + 9
4. 23 = x + 4
x = 15
x = 87
x = 7
x = 19
2-6 Subtraction Equations
Course 1
Problem of the Day
Bruce has 25 CDs remaining after giving 14 to John, 17 to Mary, and 25 to Sue. How many CDs did he begin with?81
2-6 Subtraction Equations
Course 1
Learn to solve whole-number subtraction equations.
2-6 Subtraction Equations
Course 1
When John F. Kennedy became president of the United States, he was 43 years old, which was 8 years younger than Abraham Lincoln was when Lincoln became President. How old was Lincoln when he became president?
2-6 Subtraction Equations
Course 1
Abraham Lincoln’s age
John F. Kennedy’s age– = 8
Let a represent Abraham Lincoln’s age.
a – =8 43
a – 8 = 43
+ 8 + 8
a = 51
Abraham Lincoln was 51 years old when he became president.
2-6 Subtraction Equations
Course 1
y – 23 = 39 23 is subtracted from y.
+ 23
y = 62
Add 23 to both sides to undo the subtraction.
Check y – 23 = 39Substitute 62 for y in the equation.
Solve y – 23 = 39. Check your answer.
62 is the solution.39 = 39?
Additional Example 1A: Solving Subtraction Equations
62 – 23 = 39?
+ 23
2-6 Subtraction Equations
Course 1
78 = s – 15 15 is subtracted from s.+ 15
93 = s
Add 15 to both sides to undo the subtraction.
Check 78 = s – 15
Substitute 93 for s in the equation.
Solve 78 = s – 15. Check your answer.
93 is the solution.78 = 78?
Additional Example 1B: Solving Subtraction Equations
78 = 93 – 15?
+ 15
2-6 Subtraction Equations
Course 1
z – 3 = 12 3 is subtracted from z.+ 3
z = 15
Add 3 to both sides to undo the subtraction.
Check z – 3 = 12
Substitute 15 for z in the equation.
Solve z – 3 = 12. Check your answer.
15 is the solution.12 = 12?
Additional Example 1C: Solving Subtraction Equations
15 – 3 = 12?
+ 3
2-6 Subtraction Equations
Course 1
a – 4 = 7 4 is subtracted from a.+ 4
a = 11
Add 4 to both sides to undo the subtraction.
Check a – 4 = 7
Substitute 11 for a in the equation.
Solve a – 4 = 7. Check your answer.
11 is the solution.7 = 7?
11 – 4 = 7?
+ 4
Check It Out: Example 1A
2-6 Subtraction Equations
Course 1
57 = c – 13 13 is subtracted from c.
+ 13
70 = c
Add 13 to both sides to undo the subtraction.
Check 57 = c – 13
Substitute 70 for c in the equation.
Solve 57 = c – 13. Check your answer.
70 is the solution.57 = 57?
57 = 70 – 13?
+ 13
Check It Out: Example 1B
2-6 Subtraction Equations
Course 1
g – 62 = 14 62 is subtracted from g.
+ 62
g = 76
Add 62 to both sides to undo the subtraction.
Check g – 62 = 14
Substitute 76 for g in the equation.
Solve g – 62 = 14. Check your answer.
76 is the solution.14 = 14?
76 – 62 = 14?
+ 62
Check It Out: Example 1C
2-6 Subtraction Equations
Course 1
1. x – 9 = 21
2. 14 = x – 3
3. x – 7 = 11
4. 16 = x – 14
5. x – 9 = 11
Lesson Quiz
6. Susan is taller than James. The difference in their height is 4 inches. James is 62 inches tall. How tall is Susan?
x = 30
x = 17
x = 18
x = 30
x = 20
66 inches