Write the following problem on the board:
- How is this problem different from the division problems you have been doing so far? (Students may respond that the dividend is not a multiple of ten, or that there is not an obvious related division fact.)
- What is your guess for a number close to the quotient? (Answers may vary; a reasonable answer might be between 50 and 80.)
- How can you test if your guess is close to the actual answer? (Multiply the guessed number by seven to see how close the product is to 468.)
- What fact families that use 7 will be helpful in finding an estimate? (7 × 6 = 42 and 7 × 7 = 49)
- Why are those multiplication facts helpful? (Possible response: If you multiply the products 42 and 49 by 10, you get products close to 468, the dividend in this problem.)
- 7 × what numbers is close to 468? Why? (468 is between 7 × 60 = 420 and 7 × 70 = 490.)
These questions lead to a discussion about estimating with division. Tell students that they can estimate answers to division problems by making an educated guess and testing the guess using multiplication. The product can then help with making a better guess.
Direct students to the Estimate with Division pages in the Student Activity Book. Show a display of the first page. Compare the class's estimates for 
with the one shown on the page.
Solve the first problem from this page in class together before asking students to complete the remaining problems independently or in groups.
As students think about their estimates to Question 1, ask:
- What numbers might you use to estimate the quotient in the problem 536 ÷ 8 (Possible response: I used multiples of 10 to estimate.)
- What multiples of 10 would be a good estimate to start with? (Possible response: 8 × 50 = 400, 8 × 60 = 480, 8 × 70 = 560)
- What fact families will be helpful in estimating 546 ÷ 8?(8 × 6 = 48, or 8 × 7 = 56)
If students have problems identifying the fact families and corresponding multiples of 10 that are close to the dividend, ask questions similar to these for Question 2, 235 ÷ 9, in the Student Activity Book.
- What multiples of 10 are close to 235? (200, 210, 220, 230, 240)
- What multiplication facts with 9 will help you find a good estimate? Look on your Facts I Know charts. (9 × 2 = 18 and 9 × 3 = 27)
- What multiples of 10 will you use? (9 × 20 = 180 and 9 × 30 = 270)
- What is a reasonable estimate for 235 ÷ 9? (a number between 20 and 30)
Students may report an estimate as a single number or as lying within a range between two numbers. Encourage them to do both. For Question 1, a good estimate might be either 70, or a number between 60 and 70. If estimates are given as a range, push students to think about which end of the range the answer lies closer to. Reasonable estimates will also help students find good initial partial products for solving division problems by paper-and-pencil methods in future lessons.
