3. Problem of the Day Hank wanted to record the number of marbles he lost to his friend Marcus each day for 5 days. He forgot to record one day, but for the other days he wrote 8, 2, 3, and 4. The average number he lost was 4. What number did he forget to write? 3
4. Preview of MA.7.A.3.1 Use and justify the rules for…dividing…integers. Preview of MA.7.A.3.2 Divide…integers,…including solving problems in everyday contexts. Sunshine State Standards
5. Multiplication and division are inverse operations. To solve a division problem, think of the related multiplication.
6. Additional Example 1: Dividing Integers Find each quotient. A. –30 ÷ 6 B. –42 ÷ (–7) Think: What number times 6 equals –30? – 5 • 6 = –30, so –30 ÷ 6 = –5. Think: What number times –7 equals –42? 6 • (–7) = –42, so –42 ÷ (–7) = 6.
7. Check It Out: Example 1 Find each quotient. A. –15 ÷ 5 B. –36 ÷ (–6) Think: What number times 5 equals –15? – 3 • 5 = –15, so –15 ÷ 5 = –3. Think: What number times –6 equals –36? 6 • (–6) = –36, so –36 ÷ (–6) = 6.
8. If the signs are the same, the product is positive. 24 ÷ 3 = 8 –6 ÷ (–3) = 2 If the signs are different, the quotient is negative. – 20 ÷ 5 = –4 72 ÷ (–8) = –9 Zero divided by any integer equals 0. = 0 = 0 You cannot divide any integer by 0. Because division is the inverse of multiplication, the rules for dividing integers are the same as the rules for multiplying integers. Dividing Integers 0 14 __ 0 – 11 __
9. Additional Example 2A: Evaluating Integer Expressions Evaluate for each value of d . d = 16 Write the expression. = 16 ÷ 4 Substitute 16 for d. = 4 The signs are the same, so the answer is positive. d 4 __ d 4 __ 16 4 __
10. Additional Example 2B: Evaluating Integer Expressions Evaluate for each value of d . d = –24 Write the expression. = –24 ÷ 4 Substitute –24 for d. = –6 The signs are different, so the answer is negative. d 4 __ d 4 __ -24 4 ___
11. Additional Example 2C: Evaluating Integer Expressions Evaluate for each value of d . d = –12 Write the expression. = –12 ÷ 4 Substitute –12 for d. = –3 The signs are different, so the answer is negative. d 4 __ d 4 __ -12 4 ___
12. Check It Out: Example 2A Evaluate for each value of c . c = –15 Write the expression. = –15 ÷ 3 Substitute –15 for c. = –5 The signs are different, so the answer is negative. c 3 __ c 3 __ -15 3 ___
13. Check It Out: Example 2B Evaluate for each value of c . c = 12 Write the expression. = 12 ÷ 3 Substitute 12 for c. = 4 The signs are the same, so the answer is positive. c 3 __ c 3 __ 12 3 ___
14. Check It Out: Example 2C Evaluate for each value of c . c = 27 Write the expression. = 27 ÷ 3 Substitute 27 for c. = 9 The signs are the same, so the answer is positive. c 3 __ c 3 __ 27 3 __
16. Lesson Quiz Find each quotient. 1. 18 ÷ (–3) 2. –36 ÷ (–6) 3. –64 ÷ (–8) 4. –45 ÷ 3 Evaluate for each value of x . 5. x = –12 6. x = 20 7. Carmen’s mom has $3,200 in her bank account. If she uses the money to make monthly rent payments of $375, how many whole payments can she make? 6 – 6 8 – 15 – 3 5 8 x 4 __
17. 1. Find the quotient. 32 ÷ (–4) A. –8 B. –28 C. –26 D. –128 Lesson Quiz for Student Response Systems
18. 2. Find the quotient. – 55 ÷ (–5) A. 60 B. 11 C. –60 D. –11 Lesson Quiz for Student Response Systems
19. 3. Evaluate z ÷ 5 for z = –45. A. –9 B. –40 C. –50 D. –225 Lesson Quiz for Student Response Systems
20. 4. Stacey has 1,500 grams of flour. She needs 275 grams of flour to bake a cake. How many whole cakes can she bake? A. 3 B. 4 C. 5 D. 6 Lesson Quiz for Student Response Systems
