Get Ready to Multiply Mentally !

1. Lesson 6: I can connect area diagrams and the distributive property to partial products of the standard algorithm without renaming. 5th Grade Module 2 – Lesson 6

2. Get Ready toMultiply Mentally! You will need the Pattern Sheet (2.B.49) You will have 2 minutes to do as many problems as you can! Remember to use mental math strategies! 5th Grade Module 2 – Lesson 6

3. Get Your White Board Ready!Multiply by Multiples of 100 21 x 100 = ____ 2,100 Say the multiplication sentence. Say the multiplication sentence. 8,400 2,100 x 4 = ____ Say 21 x 400 as a three-step multiplication sentence, taking out the hundred. 21 x 400 = ____ 21 x 100 x 4 = 8,400 21 x 400 = 8,400 5th Grade Module 2 – Lesson 6

4. Get Your White Board Ready!Multiply by Multiples of 100 312 x 100 = _____ 31,200 Say the multiplication sentence. Say the multiplication sentence. 93,600 31,200 x 3 = ____ Say 312 x 300 as a three-step multiplication sentence, taking out the hundred. 312 x 300 = ____ 312 x 100 x 3 =93,600 312 x 300 = 93,600 5th Grade Module 2 – Lesson 6

5. Get Your White Board Ready!Multiply by Multiples of 100 2,314 x 100 = _____ 231,400 Say the multiplication sentence. Say the multiplication sentence. 2,314 x 2 = ____ 4,628 Say 2,314 x 200 as a three-step multiplication sentence, taking out the hundred. 2,314 x 200 = ____ 2,314 x 100 x 2 = 462,800 2,314 x 200 = 462,800 5th Grade Module 2 – Lesson 6

6. Let’s Review MultiplyingUsing the Area Model & Algorithm(solve in your notebook) 43 x 12 = _____ Solve each using an area model Solve each using the standard algorithm 243 x 12 = _____ Solutions on next slide. 312 x 23= _____ 5th Grade Module 2 – Lesson 6

7. 4 3 x 1 2 8 6 + 4 3 0 5 1 6 3 12 x 2 3 9 3 6 + 6 24 0 71 7 6 2 4 3 x 1 2 4 8 6 + 2 4 3 0 2 9 1 6 43 312 243 2 3 2 86 936 486 430 6,240 2,430 10 10 20 5th Grade Module 2 – Lesson 6

8. Application Problem Scientists are creating a material that may replace damaged cartilage in human joints. This hydrogel can stretch to 21 times its original length. If a strip of hydrogel measures 3.2 cm, what would its length be when stretched to capacity? To watch a video of a hydrogel in action click here 5th Grade Module 2 – Lesson 6

9. Use ink to share solution or Click to Reveal Answer to Application Problem 5th Grade Module 2 – Lesson 6

10. Concept Development Divide your white board into two sections. On one side we’ll solve with an area model, and on the other side, we will connect it to the standard algorithm. Area Model Standard Algorithm 64 x 73 Solve using the standard algorithm. Check with your partner that you solved it correctly! Let’s represent 64 groups of 73. However, how can we decompose 73 to make finding these partial products easier to solve? Let’s fill in each partial product. Then add them up! Yes! We can split it into 70 + 3. Let’s re-create our area model. 280 12 73 x 64 2 9 2 +4 3 8 0 4 6 7 2 73 70 + 3 4200 180 4 4 60 60 4200 + 180 + 280 + 12 = 4,672 Let’s compare the two models. What do you notice? 5th Grade Module 2 – Lesson 6

11. Let’s Just Practice Creating an Area Model *Draw using ink tools. Draw an area model for 56 x 34 Draw an area model for 326 x 27 5th Grade Module 2 – Lesson 6

12. 814 x 39 Partner A Solve using the Standard Algorithm Partner B Solve using the Area Model Compare your Solutions 4 800 10 9 7326 +24420 31,746 30 5th Grade Module 2 – Lesson 6

13. 624 x 82 Partner B Solve using the Standard Algorithm Partner A Solve using the Area Model Compare your Solutions 4 600 20 2 1248 +49920 51,168 80 5th Grade Module 2 – Lesson 6

14. Get Ready to Complete theProblem Set on Your Own! Complete Pages 2.B.50 & 2.B.51 You will have 10-15 minutes to work. Try your Best! 5th Grade Module 2 – Lesson 6

15. LET’S Debrief • What pattern did you notice between Parts (a) and (b) of Problem 1? How did this slight difference in factors impact your final product? • Explain to your partner how you recorded the regrouping in Problem 2(a). What were you thinking and what did you write as you multiplied 9 tens times 5 tens? • Let’s think about a problem like 23 × 45 and solving it with the algorithm. What is the first partial product that we would find? (3 × 45) The second? (20 × 45) Would this be the only order in which we could find the partial products? What else could we do? • What information did you need before you could find the cost of the carpet in Problem 3? How did you find that information? Why is area measured in square units? 5th Grade Module 2 – Lesson 6

16. EXIT TICKET Page 2.B.52 5th Grade Module 2 – Lesson 6