11 6 Multiplying Integers Warm Up Problem of

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

11 -6 Multiplying Integers Students Try These! Warm Up Find each product. 1. 3. 5. 7. Course 1 8 • 4 3 • 9 80 • 6 40 • 90 32 27 480 3, 600 2. 4. 6. 8. 7 • 12 84 6 • 5 30 50 • 6 300 20 • 700 14, 000

11 -6 Multiplying Integers Skip this one! 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 1

11 -6 Multiplying Integers Learn to multiply integers. Course 1

11 -6 Multiplying Integers Record this one! Numbers 3 • 2 – 3 • 2 Words 3 groups of 2 the opposite of 3 groups of 2 Addition 2+2+2 –(2 + 2) Product 6 – 6 Course 1

11 -6 Multiplying Integers Record this one! Numbers Words Addition Product Course 1 3 • (– 2) – 3 • (– 2) 3 groups of – 2 the opposite of 3 groups of – 2 (– 2) + (– 2) –[(– 2) + (– 2)] – 6 6

11 -6 Multiplying Integers Additional Example 1: Multiplying Integers Find each product. A. 5 • 2 = 10 Write these two examples. Think: 5 groups of 2. B. 4 • (– 5) = – 20 Think: 4 groups of – 5. Remember! To find the opposite of a number, change the sign. The opposite of 6 is – 6. The opposite of – 4 is 4. Course 1

11 -6 Multiplying Integers Additional Example 1: Multiplying Integers Find each product. Write these two examples. C. – 3 • 2 = – 6 D. – 2 • (– 4) = 8 Think: the opposite of 2 groups of – 4. Course 1 Think: the opposite of 3 groups of 2.

11 -6 Multiplying Integers Check It Out: Example 1 Find each product. Skip this one A. 3 • 4 = 12 Think: 3 groups of 4. B. 2 • (– 7) = – 14 Course 1 Think: 2 groups of – 7.

11 -6 Multiplying Integers Check It Out: Example 1 Find each product. Skip this one! C. – 5 • 3 = – 15 Think: the opposite of 5 groups of 3. D. – 4 • (– 6) = 24 Think: the opposite of 4 groups of – 6. Course 1

11 -6 Multiplying Integers Record this slide! 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. 0 Course 1 • 9=0 (– 12) • 0=0

11 -6 Multiplying Integers Additional Example 2: Evaluating Integer Expressions Record this Evaluate – 7 x for each value of x. one! A. x = – 3 – 7 x Write the expression. – 7 • (– 3) Substitute – 3 for x. The signs are the same, so the answer 21 is positive. B. x = 5 – 7 x Write the expression. – 7 • 5 Substitute 5 for x. – 35 The signs are different, Remember! so the answer is negative. – 7 x means – 7 • x. Course 1

11 -6 Multiplying Integers Check It Out: Example 2 Evaluate – 4 y for each value of y. A. y = – 2 – 4 y Write the expression. – 4 • (– 2) Substitute – 2 for y. 8 B. y = 7 – 4 y – 4 • 7 – 28 Course 1 Record this one! The signs are the same, so the answer is positive. Write the expression. Substitute 7 for y. The signs are different, so the answer is negative.

11 -6 Multiplying Insert Lesson Integers Title Here Lesson Quiz Find each product. 1. 6 • 3. – 9 (4) 24 • (– 2) 18 2. 3 • 4. – 6 Skip this one! (– 2) – 6 • 5 – 30 5. Evaluate 3 y for y = – 7. – 21 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? – 2 Course 1