lesson menu main idea and new vocabulary example 1:add integers with the same sign key concept:add...
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Main Idea and New Vocabulary
Example 1:Add Integers with the Same Sign
Key Concept: Add Integers with the Same Sign
Example 2:Add Integers with the Same Sign
Key Concept: Additive Inverse Property
Example 3: Add Integers with Different Signs
Example 4: Add Integers with Different Signs
Key Concept: Add Integers with Different Signs
Example 5: Add Integers with Different Signs
Example 6: Add Integers with Different Signs
Example 7: Add Integers with Different Signs
Example 8: Real-World Example
• Add integers.
• opposites
• additive inverse
Add Integers with the Same Sign
Find –6 + (–3).
• Start at 0. Move 6 units to the left to show –6.
• From there, move 3 units to the left to show –3.
Answer: So, –6 + (–3) = –9.
–6–3
A. –4
B. –2
C. 0
D. 4
Find –2 + (–2).
Find –34 + (–21).
Add Integers with the Same Sign
–34 + (–21) = –55 Both integers are negative, so the sum is negative.
Answer: So, –34 + (–21) = –55.
A. 22
B. 6
C. –6
D. –22
Find –14 + (–8).
Add Integers with Different Signs
Find 8 + (–7).
Answer: So, 8 + (–7) = 1.
+8–7
A. –4
B. –2
C. 2
D. 4
Find 3 + (–1).
Find –5 + 4.
Add Integers with Different Signs
Answer: So, –5 + 4 = –1.
–5+4
A. –11
B. –7
C. 7
D. 11
Find –9 + 2.
Add Integers with Different Signs
Find 2 + (–7).
2 + (–7) = –5 Subtract absolute values; 7 – 2 = 5. Since 7 has the greater absolute value, the sum is negative.
Answer: So, 2 + (–7) = –5.
A. 14
B. 2
C. –2
D. –14
Find 6 + (–8).
Add Integers with Different Signs
Find –9 + 6.
–9 + 6 = –3 Subtract absolute values; 9 – 6 = 3. Since 9 has the greater absolute value, the sum is negative.
Answer: So, –9 + 6 = –3.
A. 12
B. 10
C. –10
D. –12
Find –11 + 1.
Add Integers with Different Signs
Find 11 + (–4) + (–11).
11 + (–4) + (–11) = 11 + (–11) + (–4)Commutative Property (+)
= [11 + (–11)] + (–4)Associative Property (+)
= 0 + (–4) Additive Inverse Property
= –4 Additive Identity Property
Answer: The solution is –4.
A. –12
B. –10
C. –7
D. –2
Find 5 + (–7) + (–5).
FINANCIAL LITERACY Small businesses manage their inventory using integers. The cost of goods sold is calculated as starting inventory plus cost of items bought during the year plus a negative value on the ending inventory for the year. For example, a small horse farm owner might have a starting inventory of horses valued at $9,500, purchase a colt during the year for $2,000, and have an ending inventory value of $6,000. What is the cost of goods sold? Write an addition sentence to describe this situation. Then find the sum and explain its meaning.
$9,500 + $2,000 + (–$6,000) = $11,500 + (–$6,000) $9,500 + $2,000 = $11,500
= $5,500 Subtract the absolute values. Since $11,500 has the greater absolute value, the sum is positive.
Answer: The cost of goods sold is $5,500.
A. Point E is 4 feet lower than point A.
B. Point E is 6 feet lower than point A.
C. Point E is 8 feet lower than point A.
D. Point E is 10 feet lower than point A.
ROLLER COASTERS The graphic shows the change in height at several points on a roller coaster. Write an addition sentence to find the height at point E in relation to point A.
20 + (–32) + 16 + (–10) = –6