How would you use estimation to find the answer to 2,860 ÷ 13?

In this lesson you will learn how to divide by estimating and adjusting the quotient.

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

Challenging problems can be broken into smaller parts 20 x = 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 x 10 = x 2 = x 13 = 260

Let’s Review A Common Mistake Dividing with very small numbers 1,215 ÷ 10 Running totalQuotient 1, (2x10)=20 1,196

Let’s Review Core Lesson 2,860 ÷ 13 Smart rounding ≈ 2,400 ÷ 12 Smart estimate ≈ divides easily by 12

Let’s Review Core Lesson 2,860 ÷ 13 This makes sense since our smart estimate was 200 This makes sense since our smart estimate was 200 Running total Quotient 2, x 13= x 13= 1, x 13 = 2,600 -(200 x 13) = 2, x 1= x 2 = x 20 = 260 -(20 x 13) =

Let’s Review Core Lesson There are 1,716 stamps for 16 students. How many stamps does each student get? Smart rounding ≈ 1,600 ÷ 16 Smart estimate ≈ 100 1,600 divides easily by 16

Let’s Review Core Lesson 1,716 ÷ 16 This makes sense since our smart estimate was 100 This makes sense since our smart estimate was 100 Running total Quotient 1, x 16= x 16= 1,600 -(100 x 16) = 1, x 16= 160 Too large 5 x 16 = 80 -(5 x 16) = x 16 = 32 -(2 x 16) =32 4 left 2 107

In this lesson you have learned how to divide by estimating and adjusting the quotient.

Let’s Review Guided Practice Use estimation and adjustment to solve 2,860 ÷ 13. Running total Quotient 2860

Let’s Review Extension Activities Use estimation and adjustment to solve 2,575 ÷ 23. Explain your work. Susanna is sorting her giant button collection into boxes. She wants each box to have the same number of buttons. She has 3,920 buttons. If she has 15 boxes, how many buttons will she put in each box. Will she have any left over?

Let’s Review Quick Quiz Which table shows how to divide 1,655 ÷ 15? Running total Quotient 1,655 -(100 x 15)= (10 x 15) = left110 Running total Quotient 1,655 -(9 x 112)= (40 x 15) = left152 Running total Quotient 1,655 -(100 x 16)= (10 x 5) = left110 AB C

Let’s Review Quick Quiz Which table shows how to divide 1,248 ÷ 12? Running total Quotient 1,248 -(100 x 12)=1, (12 x 20) = left110 Running total Quotient 1,248 -(12 x 100)=1, (12 x 4) = Running total Quotient 1,248 -(100 x 12)=1, (12 x 12)= left110 AB C