Lesson Menu 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
Main Idea/Vocabulary Add integers. opposites additive inverse
Example 1 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
Example 1 CYP A.–4 B.–2 C.0 D.4 Find –2 + (–2).
Key Concept 2
Example 2 Find –34 + (–21). Add Integers with the Same Sign – 34 + ( – 21) = –55Both integers are negative, so the sum is negative. Answer: So, –34 + (–21) = –55.
Example 2 CYP A.22 B.6 C.–6 D.–22 Find –14 + (–8).
Key Concept 3
Example 3 Add Integers with Different Signs Find 8 + (–7). Answer: So, 8 + (–7) = –7
Example 3 CYP A.–4 B.–2 C.2 D.4 Find 3 + (–1).
Example 4 Find – Add Integers with Different Signs Answer: So, –5 + 4 = –1. –5 +4
Example 4 CYP A.–11 B.–7 C.7 D.11 Find –9 + 2.
Key Concept 6
Example 5 Add Integers with Different Signs Find 2 + (–7). 2 + (–7) = –5Subtract absolute values; 7 – 2 = 5. Since 7 has the greater absolute value, the sum is negative. Answer: So, 2 + (–7) = –5.
Example 5 CYP A.14 B.2 C.–2 D.–14 Find 6 + (–8).
Example 6 Add Integers with Different Signs Find – – = –3Subtract absolute values; 9 – 6 = 3. Since 9 has the greater absolute value, the sum is negative. Answer: So, –9 + 6 = –3.
Example 6 CYP A.12 B.10 C.–10 D.–12 Find –
Example 7 Add Integers with Different Signs Find 11 + (–4) + (–11) (–4) + (–11) = 11 + (–11) + (–4)Commutative Property (+) = [11 + (–11)] + (–4)Associative Property (+) = 0 + (–4)Additive Inverse Property = –4Additive Identity Property Answer: The solution is –4.
Example 7 CYP A.–12 B.–10 C.–7 D.–2 Find 5 + (–7) + (–5).
Example 8 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.
Example 8 $9,500 + $2,000 + (–$6,000) = $11,500 + (–$6,000)$9,500 + $2,000 = $11,500 = $5,500Subtract the absolute values. Since $11,500 has the greater absolute value, the sum is positive. Answer: The cost of goods sold is $5,500.
Example 8 CYP 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 (–32) (–10) = –6