3. Do Now Order the following fractions from least to greatest: ½, 1/8, 1/3, 1/9 2/3, 1/6, 3/6, 2/5, 4/7 Homework: lattice multiplication worksheet

4. Lattice Multiplication By Mrs. Heter

5. Standard/ Objective 6.N.17 Multiply and divide fractions with unlike denominators Objective: SWBAT multiply 2 digit by 2 digit numbers using the lattice method.

6. Flow of the Day Do Now 5 min Intro to new material 15 min Guided practice 15 min Independent practice 20 min Exit Slip 5 min

7. Upon completion of this exercise, you will:

8. Discover the history of lattice multiplication;

9. Upon completion of this exercise, you will: Discover the history of lattice multiplication; Identify the four step process for completing a 2 by 1 lattice;

10. Upon completion of this exercise, you will: Discover the history of lattice multiplication; Construct your own 2 by 1 lattice grid; Identify the four step process for completing a 2 by 1 lattice;

11. Upon completion of this exercise, you will: Discover the history of lattice multiplication; Construct your own 2 by 1 lattice grid; Identify the four step process for completing a 2 by 1 lattice; Apply the Lattice Method to multiplication problems

12. So, what is Lattice Multiplication, anyway?

13. Lattice multiplication is a method of multiplication that will work for all multi- digit multiplication problems! Lattice keeps your numbers organized and provides a systematic way to solve multiplication problems.

14. Is Lattice Multiplication New?

15. NO! In fact, the Lattice method of multiplication appears in the first printed arithmetic book. Printed in Treviso, Italy in 1478 this book shows this exact method as well as some variations of the long multiplication algorithm commonly taught today. Lattice

16. COOL!

17. 4 Simple Steps to Lattice Multiplication 1. Make the grid/ lattice 2. Write the factors outside the grid 3. Multiply 4. Add to get your answer

19. Step One: Make the Lattice Grid First draw a box and divide it into 2 equal sections.

20. Step One: Make the Lattice Grid Next, divide those boxes diagonally from the top right to the bottom left corner.

21. Step Two: Write the factors on the grid Now what? Simple, ask someone to give you a multi-digit multiplication problem to solve! Now add these numbers to the grid. 43 x 5 = ?

22. Fill in the Lattice Fill in the numbers like this… 4 3 5

23. Step Three: Multiply Now multiply! 43 x 5 = ?

24. Then Multiply the Outside! First multiply 5x3 and write your answer in the lattice as shown. 1 5 4 5 3

25. Then Multiply the Outside! Next, multiply 5x4. Write your answer in the top left box of your lattice grid. 2 0 1 5 4 5 3

26. Wait! You’re Not Finished Yet!

27. Step Four: Add the Inside Finally, add the numbers in the diagonals to get the solution. 5 is all by itself so simply bring that number down. 2 0 1 5 4 5 3 5

28. Step Four: Add the Inside Finally, add the numbers in the diagonals to get the solution. Next, add 1 + 0, and write the sum under the lattice. 2 0 1 5 4 5 3 51

29. Step Four: Add the Inside Finally, add the numbers in the diagonals to get the solution. Finally, bring down the 2. 2 0 1 5 4 5 3 512

30. Now you’ve got your answer! 43 x 5 = 215

31. Now You Try It. Using the graph paper in front of you, draw a square around any two of the blocks on your paper.

32. Now You Try It. Next, divide those boxes diagonally from the top right to the bottom left corner.

33. Fill in the Lattice Fill in the numbers like this… 3 9 6

34. Then Multiply the Outside! First multiply 6x9 and write your answer in the lattice as shown. 5 4 3 6 9

35. Then Multiply the Outside! Next, multiply 6x3. Write your answer in the top left box of your lattice grid. 1 8 5 4 3 6 9

36. Add the Inside Finally, add the numbers in the diagonals to get the solution. 4 is all by itself so simply bring that number down. 1 8 5 4 3 6 9 4

37. Add the Inside Finally, add the numbers in the diagonals to get the solution. Next, add 5 + 8, and write the sum under the lattice. 1 8 5 4 3 6 9 4 3 1

38. Step Three: Add the Inside Finally, add the numbers in the diagonals to get the solution. Finally, add the 1 + 1 And write the sum below the lattice. 1 8 5 4 3 6 9 4 3 1 2

39. Now you’ve got your answer! 39 x 6 = 234

40. Let’s Practice Together! Practice is FUN!

41. Try 71 x 3

42. Are you ready for more?????

43. Ready, Set, Let’s Solve Lattice Multiplication Problems! Please open your math journal to page 231

44. Try 8 x 45

45. Try 5 x 23

46. Try 6 x 431

48. Hmmm, what will we need to do differently to multiply a THREE digit number?

49. Try 6 x 431

50. Let’s Take a Quick Lattice Multiplication Quiz to see how much you remember!

51. Yes or No? Lattice multiplication is a NEW method of multiplying numbers? CLAP your hands ONE TIME for YES. STOMP your feet ONE TIME for NO.

52. No! Lattice multiplication has been in use since the late 1400’s!

53. Yes or No? The process for solving Lattice Multiplication involves 4 steps. CLAP your hands ONE TIME for YES. STOMP your feet ONE TIME for NO.

54. 4 Simple Steps to Lattice Multiplication 1. Make the grid/ lattice

55. 4 Simple Steps to Lattice Multiplication 1. Make the grid/ lattice 2. Write the factors on the outside of the grid

56. 4 Simple Steps to Lattice Multiplication 1. Make the grid/ lattice 2. Write the factors on the outside of the grid 3. Multiply

57. 4 Simple Steps to Lattice Multiplication 1. Make the grid/ lattice 2. Write the factors on the outside of the grid 3. Multiply 4. Add to get your answer

58. You’ve just learned how to solve multi-digit multiplication problems using the Lattice Multiplication Algorithm! Congratulations!

59. Now, finish the problems on the right column of page 231. Ask your seat mate or raise your hand if you need assistance. Congratulations!