Module 2 – Lesson 18 Objective: Use basic facts to estimate quotients with two-digit divisors.

Fluency Practice – Group Count by Multiples of 10 Count by multiples of 6 tens up to 42 tens (skip count by 6 tens). – 6 tens, 12, tens, 18 tens, 24 tens, 30 tens, 36 tens, 42 tens. Count by multiples of 8 tens up to 64 tens (skip count by 8 tens). – 8 tens, 16 tens, 24 tens, 32 tens, 40 tens, 48 tens, 56 tens, 64 tens Count by multiples of 9 tens up to 108 tens (skip count by 9 tens). – 9 tens, 18 tens, 27 tens, 36 tens, 45 tens, 54 tens, 63 tens, 72 tens, 81 tens, 90 tens, 99 tens, 108 tens

Fluency Practice – Divide by Multiples of 10, 100, and ,000 ÷ 40 =15,000 ÷ 50 = 12,000 ÷ 400 =15,000 ÷ 300 = 12,000 ÷ 4,000 =24,000 ÷ 8,000 = 49,000 ÷ 700 =490,000 ÷ 7,000 = 35,000 ÷ 70 =35,000 ÷ 700 = 480,000 ÷ 800 =480,000 ÷8,000 = 108,000 ÷ 900 =99,000 ÷ 9,000 =

Fluency Practice – Estimate and Divide 812 ÷ 39 = – 800 ÷ 40 = ÷ 31 = – 180 ÷ 30 = ÷ 72 = – 420 ÷ 70 = ÷ 97 = – 800 ÷ 100 = 8 8,191 ÷ 92 = – 8,100 ÷ 90 = 90

Application Problem Sandra bought 38 DVD movies for $874. Give an estimate of the cost of each DVD movie. – 874 ÷ 38 = 880 ÷ 40 = 22 The cost of each DVD movie is approximately $ ÷ 40 = 800 ÷ 10 ÷ 4 = 20 – The cost of each DVD movie is approximately $20. » Why did we use 800 instead of 900? » Why did we use 880 instead of 900?

Concept Development – Problem 1 8,095 ÷ 23 – What number should we round first? Why? The divisor, so we can determine what to round the divided to. – What would 23 round to? » 20 – What should we round 8,095 to? » 8,000 – What is another way we can look at 8,000 ÷ 20? 8,000 ÷ 10 ÷ 2 – What is 8,000 ÷ 10? » 800 – What is 800 ÷ 2? 400 – What is 8,000 ÷ 20? 400

Concept Development – Problem 2 2,691 ÷ 48 – What number should we round first? Why? The divisor, so we can determine what to round the divided to. – What would 48 round to? » 50 – What should we round 2,691 to? » 2,500 or 3,000 – What is another way we can look at 2,500 ÷ 50 or 3,000 ÷ 50? 2,500 ÷ 10 ÷ 5 or 3,000 ÷ 10 ÷ 5 – What is 2,500 ÷ 10 or 3,000 ÷ 10? » 250 or 300 – What is 250 ÷ 5 or 300 ÷ 5? 50 or 60 – What is 2,500 ÷ 50 or 3,000 ÷ 50? 50 or 60 What can be the benefit of 2 estimates? – It can help narrow down what the actual answer will be between.

Concept Development – Problem 3 5,484 ÷ 71 – What number should we round first? Why? The divisor, so we can determine what to round the divided to. – What would 71 round to? » 70 – What should we round 5,484 to? » 5,600 – What is another way we can look at 5,600 ÷ 70? 5,600 ÷ 10 ÷ 7 – What is 5,600 ÷ 10? » 560 – What is 560 ÷ 7? 80 – What is 5,600 ÷ 70? 80

Concept Development – Problem 4 9,215 ÷ 95 – What number should we round first? Why? The divisor, so we can determine what to round the divided to. – What would 95 round to? » 90 or 100 – What should we round 9,000 to? » 9,000 – What is another way we can look at 9,000 ÷ 90 or 9,000 ÷ 100? 9,000 ÷ 10 ÷ 9 or 9,000 ÷ 10 ÷ 10 – What is 9,000 ÷ 10? » 900 – What is 900 ÷ 9 or 900 ÷ 10? 100 or 90 – What is 9,000 ÷ 90 or 9,000 ÷ 100? 100 or 90 – What does this tell us about the actual answer? The actual answer should be between 90 and 100.

Concept Development – Problem 4 9,215 ÷ 95 – What number should we round first? Why? The divisor, so we can determine what to round the divided to. – What would 95 round to? » 90 or 100 – What should we round 9,000 to? » 9,000 – What is another way we can look at 9,000 ÷ 90 or 9,000 ÷ 100? 9,000 ÷ 10 ÷ 9 or 9,000 ÷ 10 ÷ 10 – What is 9,000 ÷ 10? » 900 – What is 900 ÷ 9 or 900 ÷ 10? 100 or 90 – What is 9,000 ÷ 90 or 9,000 ÷ 100? 100 or 90 – What does this tell us about the actual answer? The actual answer should be between 90 and 100.

End of Lesson Activities Debrief Problem Set Homework Exit Ticket

Problem Set 1. Estimate the quotient for the following problems. The first one is done for you. a. 5,738 ÷ 21 = 6,000 ÷ 20 = 300 b. 2,659 ÷ 28 = _______ ÷ ______ = ________ c. 9,155 ÷ 34 = ________ ÷ ______ = ________ d. 1,463 ÷ 53e. 2,525 ÷ 64f. 2,271 ÷ 72 g. 4,901 ÷ 75h. 8,515 ÷ 81i. 8,515 ÷ 89 j. 3,925 ÷ 68k. 5,124 ÷ 81l. 4,945 ÷ 93 m. 5,397 ÷ 94n. 6,918 ÷ 86o. 2,806 ÷ 15 2.A swimming pool requires 672 ft 2 of floor space. The length of the swimming pool is 32 ft. Estimate the width of the swimming pool.

Problem Set 3. Janice bought 28 apps for her phone that, altogether, used 1,348 MB of space. a.If each app used the same amount of space, about hw many MB of memory did each app use? Show your estimated work. b.If half of the apps were free and the other half were $1.99 each, about how much did she spend? 4. A quart of paint covers about 85 square feet. About how many quarts would you need to cover a fence with an area of 3,817 square feet? 5. Peggy has saved $9,215. If she paid $45 an hour about how many hours did she work?

Exit Ticket # Estimate the quotient for the following problems. a.6,523 ÷ 21 = _________ ÷ ________ = _________ b. 8,491 ÷ 37 = ____________ ÷ _______ = ___________ c. 3,704 ÷ 53 = _________ ÷ ________ = ___________ d. 4,819 ÷ 68 = __________ ÷ ________ = ____________

Homework # Estimate the quotient for the following problems. The first one is done for you. a. 8,328 ÷ 41 = 8,000 ÷ 40 = 200 b. 2,109 ÷ 23 = ______ ÷ _______ = ________ c. 8,215 ÷ 38 = _______ ÷ ______ = ________ d. 3,861 ÷ 59e. 2,899 ÷ 66f. 5,576 ÷ 92 g. 5,086 ÷ 73h. 8,432 ÷ 81i. 9,032 ÷ 89 j. 2,759 ÷ 48k. 8,194 ÷ 91l. 4,368 ÷ 63 m. 6,537 ÷ 74n. 4,998 ÷ 48o. 6, 106 ÷ boxes of apples hold a total of 2,605 apples. Assuming each box has about the same number of apples, estimate the number of apples in each box.

Homework # A wild tiger can eat up to 55 pounds of meat in a day. About how many days would it take for a tiger to eat the following prey? PreyWeight of PreyNumber of Days Eland Antelope1,754 pounds Boar661 pounds Chital Deer183 pounds Water Buffalo2,322 pounds