1. How would you divide 1,590 ÷ 15?

2. In this lesson you will learn how to divide by using a rectangular array.

3. Let’s Review Multiplication and division are inverse operations. 45 ÷ 9 = n n x 9 = 45 9 x n = 45

4. Challenging problems can be broken into smaller parts 20 x 13 20 = 2 x 10 I know that 20 is 2 times 10 I can multiply 13 x 2 and get 26 Then I can multiply 26 x 10 and get 260 26 x 10 = 260 13 x 2 = 26 20 x 13 = 260

5. Let’s Review A rectangular array can be used to show division. 24 ÷6 = 4

6. Core Lesson 1,590 ÷ 15 Smart rounding ≈ 1,500 ÷ 15 Smart estimate ≈ 100 1,500 divides easily by 15

7. Let’s Review Core Lesson 1,590 ÷ 15 This makes sense since our smart estimate was 100 10 x 15= 150 100 x 15= 1,500 2 x 15= 30 -(20 x 13) =260 0 106 100 1,590 -1,500100 x 15 = 1,500 15 x 2 = 30 - 30 90 60 - 30 30 - 30 0 15 x 2 = 30 2 2 2 x 15 = 1,590 1,590 ÷ 15 = 106 15

8. Let’s Review Core Lesson There are 1,138 pencils for 11 students. How many pencils does each student get? Smart rounding ≈ 1,100 ÷ 11 Smart estimate ≈ 100 1,100 divides easily by 11

9. Let’s Review Core Lesson 1,138 ÷ 11 This makes sense since our smart estimate was 100 100 x 11= 1,100 10 x 11 = 110 is too big 1 03 1,138 ÷ 11 = 103 with 5 left 1,138 - 1,100 100 x 11 = 1,100 1 x 11 = 11 - 11 38 27 - 11 16 - 11 5 1 x 11 = 11 11 100 1 1 1 1 x 11 = 11 x 11= 1,133 + 5 = 1,138

10. In this lesson you have learned how to divide by using a rectangular array.

11. Let’s Review Guided Practice What is 1,590 ÷ 15?

12. Let’s Review Extension Activities Use a rectangular array to show the division of 845 ÷ 12. Make a chart to show your work. Susan has 1,115 cups to put in 25 boxes. She estimated that she would put 40 cups in each box. Using a rectangular array, show whether or not this is a good estimate.

13. Let’s Review Quick Quiz Use a rectangular array to find the answer to these problems: 1,025 ÷ 12? A. 85 with 5 left B. 85 C. 80 with 4 left A. 52 with 6 left B. 52 with 15 left C. 52 Rita needs to store 1,315 seeds. Only 25 fit in each box. How many boxes she will need?