Module 2 – Lessons 12 - 15

Day 1 Module 2 – Lesson 12

Lesson Topic: Dividing Whole Numbers and Decimals

Lesson Objective: I can…• Connect estimation with place value in order

to determine the standard algorithm for division

Opening Exercise:

Solve the following equation using any method or model and explain why you used this method

5,911 ÷ 23

Example 1:We can also use estimates before we divide to help us solve division problems. In this lesson, we will be using estimation to help us divide two numbers using

the division algorithm.

Use estimation to solve the following problem:8,085 ÷ 33

How will the estimation help us divide 8,085 by 33?

Use the standard algorithm to solve 8,085 ÷ 33

Is our answer from the standard algorithm close to the estimated answer?

Multiply to check our work

Example 2:

Use estimation and the standard algorithm to divide

1512 ÷ 27

Independent Exercises:

Estimate the quotient, use the algorithm, then check your work.

1. 1,008 ÷ 482. 2,508 ÷ 333. 2,156 ÷ 28

Closing:

How does estimation help you with the process of finding the exact quotient?

Evaluate your learning:

1234

How will you “Sharpen your Saw?”

Day 2Module 2 – Lessons 13 and 14

Lesson Topics: Dividing Multi-Digit Numbers Using the Algorithm and The Division Algorithm – Converting Decimal Division into Whole

Number Division Using Fractions

Lesson Objectives: I can…• Understand that the standard algorithm of division is simply a

tally system arranged in place value columns• Use the algorithm to divide multi-digit numbers with and without

remainders• Compare their answer to estimates to justify reasonable quotients• Understand that when we “bring down” the next digit in the

algorithm, we are distributing, recording, and shifting to the next place value

Example 1:

Create a model to divide 17,216,673 ÷ 23

Use the division algorithm to show 17,216,673 ÷ 23

Explain each step in the division algorithm

Check your work using a multiplication problem

Example 2:

Find the quotient of 31,218 ÷ 132

Should we use a model? Why or why not?

Solve using the standard algorithm.

Example 3:

Divide:

974.835 ÷ 12.45

What do you notice about these?

How can we make this easier to solve?

Independent Exercises:

1. 484,692 ÷ 78

2. 952,488 ÷ 11

Independent Exercises:

Estimate the quotient first. Use the estimate to justify the reasonableness of your answer.

3. Daryl spent $4.68 on each pound of trail mix. He spent a total of $14.04. How many pounds of trail mix

did we purchase?4. Jerod is making candles from beeswax. He has

132.72 ounces of beeswax. If each candle uses 8.4 ounces of beeswax, how many candles can he make?

Will there be any wax left?

Closing

Describe the steps that you use to change a division question with decimals to a division

question with whole numbers

Evaluate your learning:

1234

How will you “Sharpen your Saw?”

Module 2 – Lesson 15Lesson Topic: The Division Algorithm – Converting Decimal Division into Whole Number Division Using Mental Math

Lesson Objectives: I can…• Use my knowledge of dividing multi-digit numbers

to solve for quotients of multi-digits decimals• Understand mathematical concept of decimal placement in the divisor and the dividend and its

connection to multiplying by powers of 10

Opening

Start by finding the quotient of 1,728 and 32

What would happen if we multiplied the divisor by 10? (1,728 ÷ 320)

What would happen if we multiplied the dividend by 10? (17,280 ÷ 320)

Exercise 1:

537.1 ÷ 8.2

How can we make this equation easier to solve?

Solve the problem using the method from the previous problem

Exercise 2

Let’s divide 742.66 by 14.2

How can we rewrite this division problem so that the divisor is a whole number, but the

quotient remains the same?

Independent Exercises:

Solve the following division problems and check by using a multiplication problem.

1. 15.5 ÷ 6.22. 32.4 ÷ 7.23. 25.9 ÷ 7.44. 63.7 ÷ 9.8

Closing:

Based upon our work today, discuss ways you would alter the problem 4,509 ÷ .03 to make it

easier to use the long division algorithm yet yield the same answer.

Evaluate your learning:

1234

How will you “Sharpen your Saw?”