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2-6 Subtraction Equations
Warm Up
Problem of the Day
Lesson Presentation
Lesson Quizzes
2-6 Subtraction Equations
Warm Up
Solve each equation.
1. x + 7 = 22
x = 15
2. 18 + x = 105 x = 87
3. 16 = x + 9
x=7
4. 23 = x + 4
x = 19
2-6 Subtraction Equations
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
Learn to solve whole-number subtraction
equations.
2-6 Subtraction Equations
When Theodore Roosevelt became president
of the United States, he was 42 years old. He
was 27 years younger than Ronald Reagan
was when Reagan became president. How old
was Reagan when he became president?
2-6 Subtraction Equations
Let a represent Ronald Reagan’s age.
Ronald
Reagan’s age
a
–
27
=
Theodore
Roosevelt’s age
–
27
=
42
a – 27 = 42
+ 27 + 27
a
= 69
Ronald Reagan was 69 years old when he became
president.
2-6 Subtraction Equations
Additional Example 1A: Solving Subtraction
Equations
Solve y – 23 = 39. Check your answer.
y – 23 = 39
23 is subtracted from y.
+ 23 + 23
y
Add 23 to both sides to undo the
subtraction.
= 62
Check y – 23 = 39
?
62 – 23 = 39
?
Substitute 62 for y in the equation.
39 = 39  62 is the solution.
2-6 Subtraction Equations
Additional Example 1B: Solving Subtraction
Equations
Solve 78 = s – 15. Check your answer.
78 = s – 15
+ 15
+ 15
93 = s
15 is subtracted from s.
Add 15 to both sides to undo the
subtraction.
Check 78 = s – 15
?
Substitute 93 for s in the equation.
?
93 is the solution.
78 = 93 – 15
78 = 78 
2-6 Subtraction Equations
Additional Example 1C: Solving Subtraction
Equations
Solve z – 3 = 12. Check your answer.
z – 3 = 12
+3
z
+3
= 15
3 is subtracted from z.
Add 3 to both sides to undo the
subtraction.
Check z – 3 = 12
?
15 – 3 = 12
?
12 = 12 
Substitute 15 for z in the equation.
15 is the solution.
2-6 Subtraction Equations
Check It Out: Example 1A
Solve a – 4 = 7. Check your answer.
a–4=7
+4 +4
a
= 11
4 is subtracted from a.
Add 4 to both sides to undo the
subtraction.
Check a – 4 = 7
?
Substitute 11 for a in the equation.
?
11 is the solution.
11 – 4 = 7
7 = 7
2-6 Subtraction Equations
Check It Out: Example 1B
Solve 57 = c – 13. Check your answer.
57 = c – 13
+ 13
+ 13
70 = c
13 is subtracted from c.
Add 13 to both sides to undo the
subtraction.
Check 57 = c – 13
?
57 = 70 – 13 Substitute 70 for c in the equation.
?
57 = 57 
70 is the solution.
2-6 Subtraction Equations
Check It Out: Example 1C
Solve g – 62 = 14. Check your answer.
g – 62 = 14
+ 62 + 62
g
= 76
62 is subtracted from g.
Add 62 to both sides to undo the
subtraction.
Check g – 62 = 14
?
76 – 62 = 14 Substitute 76 for g in the equation.
?
14 = 14  76 is the solution.
2-6 Subtraction Equations
Lesson Quizzes
Standard Lesson Quiz
Lesson Quiz for Student Response Systems
2-6 Subtraction Equations
Lesson Quiz
1. x – 9 = 21
x = 30
2. 14 = x – 3
x = 17
3. x – 7 = 11
x = 18
4. 16 = x – 14 x = 30
5. x – 9 = 11
x = 20
6. Susan is taller than James. The difference in
their height is 4 inches. James is 62 inches
tall. How tall is Susan?
66 inches
2-6 Subtraction Equations
Lesson Quiz for Student Response Systems
1. Solve the equation x – 17 = 36.
A. x = 19
B. x = 21
C. x = 36
D. x = 53
2-6 Subtraction Equations
Lesson Quiz for Student Response Systems
2. Solve the equation 20 = x – 6.
A. x = 14
B. x = 20
C. x = 26
D. x = 40
2-6 Subtraction Equations
Lesson Quiz for Student Response Systems
3. Solve the equation y – 16 = 33.
A. y = 59
B. y = 49
C. y = 23
D. y = 17
2-6 Subtraction Equations
Lesson Quiz for Student Response Systems
4. Solve the equation 52 = y – 23.
A. y = 29
B. y = 31
C. y = 75
D. y = 84
2-6 Subtraction Equations
Lesson Quiz for Student Response Systems
5. Solve the equation x – 15 = 22.
A. x = 43
B. x = 37
C. x = 13
D. x = 7
2-6 Subtraction Equations
Lesson Quiz for Student Response Systems
6. During an NBA playoff game, Brand scored 12
points more than Cassell. If Cassell had 33
points how many points did Brand score?
A. 45 points
B. 33 points
C. 21 points
D. 12 points