Key Concept: Multiply Integers with Different Signs Main Idea Key Concept: Multiply Integers with Different Signs Example 1: Multiply Integers with Different Signs Example 2: Multiply Integers with Different Signs Key Concept: Multiply Integers with the Same Sign Example 3: Multiply Integers with the Same Sign Example 4: Multiply Integers with the Same Sign Example 5: Multiply Integers with the Same Sign Example 6: Real-World Example Example 7: Add Integers with the Same Sign Lesson Menu

Use the rules for multiplying integers. Main Idea/Vocabulary

Key Concept

Multiply Integers with Different Signs Find 5(–4). 5(–4) = –20 The integers have different signs. The product is negative. Answer: –20 Example 1

Find 2(–7). A. –14 B. –9 C. –5 D. 14 Example 1 CYP

Multiply Integers with Different Signs Find –3(9). –3(9) = –27 The integers have different signs. The product is negative. Answer: –27 Example 2

Find –2(11). A. 22 B. 13 C. –13 D. –22 Example 2 CYP

Key Concept 3

Multiply Integers with the Same Sign Find –6(–8). –6(–8) = 48 The integers have the same sign. The product is positive. Answer: 48 Example 3

Find –4(–1). A. 4 B. 3 C. –4 D. –5 Example 3 CYP

Multiply Integers with the Same Sign Find (–8)2. (–8)2 = (–8)(–8) There are two factors of –8. = 64 The product is positive. Answer: 64 Example 4

Find (–1)2. A. –2 B. –1 C. 1 D. 2 Example 4 CYP

Multiply Integers with the Same Sign Find –2(–5)(–6). –2(–5)(–6) = [–2(–5)](–6)] Associative Property = 10(–6) –2(–5) = 10 = –60 10(–6) = –60 Answer: –60 Example 5

Find –6(–7)(–2). A. –84 B. –26 C. 54 D. 84 Example 5 CYP

Answer: –1,500 feet or 1,500 feet below Earth’s surface MINES A mine elevator descends at a rate of 300 feet per minute. How far below Earth’s surface will the elevator be after 5 minutes? If the elevator descends 300 feet per minute then after 5 minutes the mine elevator will be at 5(–300) or –1,500 feet. The mine elevator will descend to 1,500 feet below the Earth’s surface. Answer: –1,500 feet or 1,500 feet below Earth’s surface Example 6

FOOD John’s freezer decreases the temperature of a casserole by 3ºF every minute. What is the change in temperature after 10 minutes? A. +30ºF B. +13ºF C. –13ºF D. –30ºF Example 6 CYP

Evaluating Expressions ALGEBRA Evaluate abc if a = –3, b = 5, and c = –8. abc = –3(5)(–8) Replace a with –3, b with 5, and c with –8. = (–15)(–8) Multiply –3 and 5. = 120 Multiply –15 and –8. Answer: The solution is 120. Example 7

ALGEBRA Evaluate rst if r = –1, s = 2, and t = –6. C. 11 D. 12 Example 7 CYP