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2-2 Adding Integers
California
Standards
NS2.3 Solve addition, subtraction,
multiplication, and division problems,
including those arising in concrete situations,
that use positive and negative integers and
combinations of these operations.
Also covered: AF1.2
Holt CA Course 1
2-2 Adding Integers
Additional Example 1A: Modeling Integer Addition
Use a number line to find the sum.
–7 + (–4)
–14
–12
–7
+(–4)
–10
–8
–6
–4
–2
0
2
Start at 0. Move left 7 units. Then move left
4 more units.
–7 + (–4) = –11
Holt CA Course 1
2-2 Adding Integers
Additional Example 1B: Modeling Integer Addition
Use a number line to find the sum.
–12 + 19
19
–12
–12
–10
–8
–6
–4
–2
0
2
4
6
Start at 0. Move left 12 units. Then move
right 19 units.
–12 + 19 = 7
Holt CA Course 1
8
2-2 Adding Integers
Adding Integers
To add two integers with the same sign,
find the sum of their absolute values. Use the
sign of the two integers.
To add two integers with different
signs, find the difference of their absolute
values. Use the sign of the integer with the
greater absolute value.
Holt CA Course 1
2-2 Adding Integers
Additional Example 2A: Adding Integers Using
Absolute Values
Find the sum.
–4 + 8
The signs are different.
Find the difference of the absolute values.
–4 + 8
Think: 8 – 4 = 4.
Use the sign of the integer
with the greater absolute
value.
4
Helpful Hint
When adding integers, think: if the signs are the same,
find the sum. If the signs are different, find the
difference.
Holt CA Course 1
2-2 Adding Integers
Additional Example 2B: Adding Integers Using
Absolute Values
Find the sum.
23 + (–35)
The signs are different. Find the difference of
the absolute values.
23 + (–35)
–12
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Think: 35 – 23 = 12.
Use the sign of the integer with the
greater absolute value (negative).
2-2 Adding Integers
Additional Example 3: Evaluating Expressions with
Integers
Evaluate x + y for x = –42 and y = 71.
x+y
–42 + 71
29
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Substitute for –42 for x and 71 for y.
The signs are different.
Think: 71 – 42 = 29
Use the sign of the integer with the
greater absolute value (positive).
2-2 Adding Integers
Additional Example 4: Application
The jazz band’s income from a bake sale was
$286. Expenses were $21. Use integer
addition to find the band’s total profit or loss.
286 + (–21)
286 – 21
265
Use negative for the expenses.
Find the difference of the
absolute values.
The answer is positive.
The band's profit was $265.
Holt CA Course 1
2-2 Adding Integers
Check It Out! Example 1
Use a number line to find the sum.
–4 + (–5)
–14
–12 –10
–4
+(–5)
–8
–6
–4
–2
0
2
Start at 0. Move left 4 spaces. Then move left
5 more spaces.
–4 + (–5) = –9
Holt CA Course 1
2-2 Adding Integers
Check It Out! Example 2
Find the sum.
–13 + (–24)
The signs are the same. Find the sum of the
absolute values.
–13 + (–24) Think: 13 + 24 = 37.
–37
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Use the sign of the two integers.
2-2 Adding Integers
Check It Out! Example 3
Evaluate x + y for x = –24 and y = 17.
x+y
–24 + 17
–7
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Substitute for –24 for x and 17 for y.
The signs are different.
Think: 24 – 17 = 7.
Use the sign of the integer with the
greater absolute value (negative).
2-2 Adding Integers
Check It Out! Example 4
The French Club was raising money for a trip
to Washington, D.C. Their car wash raised
$730. They had expenses of $52. Use integer
addition to find the club’s total profit or loss.
730 + (–52)
730 – 52
678
Use negative for the expenses.
Find the difference of the
absolute values.
The answer is positive.
The club's profit was $678.
Holt CA Course 1