5th Grade Module 2 – Lesson 19 Lesson 19: I can divide two and three digit dividends by multiples of 10 with single digit quotients and make connections to a written method. 5th Grade Module 2 – Lesson 19

Estimate and Divide 908 ÷ 28 Estimate the value… Say the divisor rounded to the nearest ten… Name the multiple of 30 that’s closest to 900… ÷ 30 900 30 5th Grade Module 2 – Lesson 19

Estimate and Divide Say the divisor rounded to the nearest ten… Estimate the value… Name the multiple of 30 that’s closest to 152… 152 ÷ 33 ÷ 30 150 5 5th Grade Module 2 – Lesson 19

Estimate and Divide Say the divisor rounded to the nearest ten… Estimate the value… Name the multiple of 100 that’s closest to 398… 398 ÷ 98 ÷ 100 400 4 5th Grade Module 2 – Lesson 19

Estimate and Divide Name the multiple of 80 that’s closest to 7,272… Say the divisor rounded to the nearest ten… Estimate the value… 7,272 ÷ 81 ÷ 80 7,200 90 5th Grade Module 2 – Lesson 19

5th Grade Module 2 – Lesson 19 Application Problem At the Highland Falls pumpkin growing contest, the prize winning pumpkin contains 360 seeds. The proud farmer plans to sell his seeds in packs of 12. How many packs can he make using all the seeds? Solution on next slide… 5th Grade Module 2 – Lesson 19

5th Grade Module 2 – Lesson 18 Solution Think of 360 as 36 tens… 360 ÷ 12 = (36 ÷ 12) x 10 = 3 x 10 = 30 packets 5th Grade Module 2 – Lesson 18

70 ÷ 30 70 ÷ 30 ≈ ÷ 30 Check: 30 x 2 = 60 70 30 Precise Answer: 2 R10 Concept Development 70 ÷ 30 70 What’s the whole (or dividend) in this problem? Let’s use rounding to find an estimated quotient! 30 What’s the divisor? Precise Answer: 2 R10 70 ÷ 30 ≈ ÷ 30 Check: 30 x 2 = 60 We are 10 off from 70! 10 is the remainder! 60 2 5th Grade Module 2 – Lesson 18

430 ÷ 60 430 ÷ 60 ≈ ÷ 60 ≈ 7 Check: 60 x 7 = 420 430 60 Precise Concept Development 430 ÷ 60 430 What’s the whole (or dividend) in this problem? Let’s use rounding to find an estimated quotient! Precise Answer: 7 R10 60 What’s the divisor? 430 ÷ 60 ≈ ÷ 60 ≈ 7 Check: 60 x 7 = 420 We are 10 off from 430! 10 is the remainder! 420 7 groups of 60 5th Grade Module 2 – Lesson 19

Let’s Try That One Again Using the Standard Algorithm! 430 ÷ 60 = 7 60 430 R 10 Why is the 7 placed above the zero? -420 10 Check: 60 x 7 = 420 (add the remainder!) 420 + 10 = 430 5th Grade Module 2 – Lesson 19

572 ÷ 90 Work independently to estimate the quotient. Check your work with your partner. Solution (use ink tools): 5th Grade Module 2 – Lesson 18

Get Ready to Complete the Problem Set on Your Own! Complete Pages 2.F.8 & 2.F.9 You will have 15 minutes to work. Try your Best! 5th Grade Module 2 – Lesson 18

5th Grade Module 2 – Lesson 18 LET’S Debrief Did anyone notice something different? Does it always make sense to use the standard algorithm? In problem 2, what was Terry’s mistake? If you had to estimate the quotient, what would you have done? What could he do to correct his mistake without erasing his work so far? What if Terry had estimated too large a quotient? What should he do? How was solving Problem 3 different from solving all the others? What did all our divisors have in common today? Did this make estimation easier? 5th Grade Module 2 – Lesson 18

5th Grade Module 2 – Lesson 18 EXIT TICKET Page 2.F.10 5th Grade Module 2 – Lesson 18