11-6 Multiplying Integers Course 1 Warm Up Warm Up Lesson Presentation Lesson Presentation Problem of the Day Problem of the Day

Warm Up Find each product Course Multiplying Integers ,600 14,000 Students Try These!

Problem of the Day Catherine has $14.00 and earns $12.00 for each lawn she mows. If she mows 4 lawns and buys 5 DVDs that cost $11.95 each, including tax, how much money does she have left? $2.25 Course Multiplying Integers Skip this one!

Learn to multiply integers. Course Multiplying Integers

Numbers3 2–3 2 Words3 groups of 2 the opposite of 3 groups of 2 Addition –( ) Product6–6 Course Multiplying Integers Record this one!

Numbers3 (–2)–3 (–2) Words3 groups of –2 the opposite of 3 groups of –2 Addition(–2) + (–2) + (–2)–[(–2) + (–2) + (–2)] Product–66 Course Multiplying Integers Record this one!

Additional Example 1: Multiplying Integers Find each product. A. 5 2 B. 4 (–5) 5 2 = 10Think: 5 groups of 2. 4 (–5) = –20 Think: 4 groups of –5. To find the opposite of a number, change the sign. The opposite of 6 is –6. The opposite of –4 is 4. Remember! Course Multiplying Integers Write these two examples.

Additional Example 1: Multiplying Integers Find each product. C. –3 2 D. –2 (–4) –3 2 = –6 Think: the opposite of 3 groups of 2. –2 (–4) = 8 Think: the opposite of 2 groups of –4. Course Multiplying Integers Write these two examples.

Check It Out: Example 1 Find each product. A. 3 4 B. 2 (–7) 3 4 = 12Think: 3 groups of 4. 2 (–7) = –14 Think: 2 groups of –7. Course Multiplying Integers Skip this one

Check It Out: Example 1 Find each product. C. –5 3 D. –4 (–6) –5 3 = –15 Think: the opposite of 5 groups of 3. –4 (–6) = 24 Think: the opposite of 4 groups of –6. Course Multiplying Integers Skip this one!

MULTIPLYING INTEGERS If the signs are the same, the product is positive. 4 3 = 12 –6 (–3) = 18 If the signs are different, the product is negative. –2 5 = –10 7 (–8) = –56 The product of any number and 0 is = 0(–12) 0 = 0 Course Multiplying Integers Record this slide!

Additional Example 2: Evaluating Integer Expressions Evaluate –7x for each value of x. A. x = –3 B. x = 5 –7xWrite the expression. –7 (–3) Substitute –3 for x. 21 The signs are the same, so the answer is positive. –7xWrite the expression. –7 5Substitute 5 for x. –35The signs are different, so the answer is negative. –7x means –7 x. Remember! Course Multiplying Integers Record this one!

Check It Out: Example 2 Evaluate –4y for each value of y. A. y = – 2 B. y = 7 –4yWrite the expression. –4 (–2)Substitute –2 for y. 8The signs are the same, so the answer is positive. –4yWrite the expression. –4 7Substitute 7 for y. –28The signs are different, so the answer is negative. Course Multiplying Integers Record this one!

Lesson Quiz Find each product (4) 2. 3 (–2) 3. –9 (–2) 4. – Evaluate 3y for y = –7. 6. During a football game, Raymond’s team lost 6 yards on each of 3 plays and gained 8 yards on each of two plays. What integer represents the total change in the team’s position? –624 Insert Lesson Title Here 18 –30 –21 –2 Course Multiplying Integers Skip this one!