Transcript Chapter 1-5 Subtracting Integers

1-5 Subtracting Integers
Warm Up
Problem of the Day
Lesson Presentation
Course 3
1-5 Subtracting Integers
Warm Up
Add.
1. –7 + 2
–5
4. –6 + (–28)
2. –12 + (–9) –21 5. 104 + (–87)
3. 32 + (–19)
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13 6. –18 + (–24)
–34
17
–42
1-5 Subtracting Integers
Problem of the Day
Copy and complete the magic square.
The magic sum is 0.
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+5
–8
+3
–2
0
+2
–3
+8
–5
1-5 Subtracting Integers
Learn to subtract integers.
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1-5 Subtracting
Insert Lesson
Title Here
Integers
Subtracting a smaller number from a
larger number is the same as finding how
far apart the two numbers are on a
number line. Subtracting an integer is the
same as adding its opposite.
SUBTRACTING INTEGERS
Words
Change the
subtraction sign
to an addition
sign and change
the sign of the
second number.
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Numbers
Algebra
2 – 3 = 2 + (–3)
4 – (–5) = 4 + 5
a – b = a + (–b)
a – (–b) = a + b
1-5 Subtracting Integers
Additional Example 1: Subtracting Integers
Subtract.
A. –7 – 4
–7 – 4 = –7 + (–4) Add the opposite of 4.
= –11
Same sign; use the sign
of the integers.
B. 8 – (–5)
8 – (–5) = 8 + 5
Add the opposite of –5.
= 13
Same sign; use the sign of
the integers.
C. –6 – (–3)
–6 – (–3) = –6 + 3 Add the opposite of –3.
= –3
6 > 3; use the sign of 6.
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1-5 Subtracting Integers
Check It Out: Example 1
Subtract.
A. 3 – (–6)
3 – (–6) = 3 + 6
=9
Add the opposite of –6.
Same signs; use the sign
of the integers.
B. –4 – 1
–4 – 1 = –4 + (–1) Add the opposite of 1.
= –5
Same sign; use the sign of
the integers.
C. –7 – (–8)
–7 – (–8) = –7 + 8 Add the opposite of –8.
=1
8 > 7; use the sign of 8.
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1-5 Subtracting Integers
Additional Example 2A: Evaluating Expressions with
Integers
Evaluate the expression for the given value of
the variable.
8 – j for j = –6
8–j
8 – (–6)
Substitute –6 for j.
=8+6
Add the opposite of –6.
= 14
Same sign; use the
sign of the integers.
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1-5 Subtracting Integers
Additional Example 2B: Evaluating Expressions with
Integers
Evaluate the expression for the given value of
the variable.
–9 – y for y = –4
–9 – y
–9 – (–4)
Substitute –4 for y.
= –9 + 4
Add the opposite of –4.
= –5
9 > 4; use the sign of 9.
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1-5 Subtracting Integers
Additional Example 2C: Evaluating Expressions with
Integers
Evaluate each expression for the given value
of the variable.
n – 6 for n = –2
n–6
–2 – 6
= –2 + (–6)
= –8
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Substitute –2 for n.
Add the opposite of 6.
Same sign; use the
sign of the integers.
1-5 Subtracting Integers
Check It Out: Example 2A
Evaluate the expression for the given value of
the variable.
11 – m for m = –3
11 – m
11 – (–3)
Substitute –3 for m.
= 11 + 3
Add the opposite of –3.
= 14
Same sign; use the
sign of the integers.
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1-5 Subtracting Integers
Check It Out: Example 2B
Evaluate the expression for the given value of
the variable.
–5 – r for r = –2
–5 – r
–5 – (–2)
Substitute –2 for r.
= –5 + 2
Add the opposite of –2.
= –3
5 > 2; use the sign of 5.
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1-5 Subtracting Integers
Check It Out: Example 2C
Evaluate each expression for the given value
of the variable.
a – 7 for a = –9
a–7
–9 – 7
= –9 + (–7)
= –16
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Substitute –9 for a.
Add the opposite of 7.
Same sign; use the
sign of the integers.
1-5 Subtracting Integers
Additional Example 3: Architecture Application
The top of the Sears Tower in Chicago, is
1454 feet above street level, while the
lowest level is 43 feet below street level.
How far is it from the lowest level to the top?
1454 – (–43)
1454 + 43
= 1497
Subtract the lowest level from
the height.
Add the opposite of (–43).
Same sign; use the sign of the
integers.
It is 1497 feet from the lowest level to the top.
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1-5 Subtracting Integers
Check It Out: Example 3
The distance from the high dive to the
swimming pool is 10 feet. The pool is 12 feet
deep. What is the total distance from the high
dive to the bottom of the pool?
10 – (–12)
Subtract the depth of the pool from the
height of the high dive.
10 + 12
Add the opposite of (–12).
= 22
Same sign; use the sign of the integers.
It is 22 feet from the diving board to the bottom
of the pool.
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1-5 Subtracting
Integers
Insert Lesson
Title Here
Lesson Quiz: Part I
Subtract.
1. –6 – (–4)
-2
2. –3 – 3
–6
3. 4 – (–5)
–1
Evaluate each expression for the given
value of the variable.
4. 9 – s for s = –5
5. –4 – w + 5 for w = 21
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14
–20
1-5 Subtracting
Integers
Insert Lesson
Title Here
Lesson Quiz: Part II
6. Suretta is flying in an airplane, and rises an
additional 20 feet. Then she descends 190
feet toward the ground. How far below her
original height did Suretta go?
170 feet
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