How would you divide

1. How would you divide 1,590 ÷ 15?

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

3. 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 Then I can multiply 26 x 10 and get 260 20 x 13 I know that 20 is 2 times 10 20 = 2 x 10 I can multiply 13 x 2 and get 26 13 x 2 = 26 26 x 10 = 260 20 x 13 = 260

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

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

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

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

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

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

11. What is 1,590 ÷ 15?

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