5th Grade Module 2 – Lesson 23

Lesson 23: I can divide three and four digit dividends by two digit divisors

resulting in two and three digit quotients, reason about the decomposition of successive

remainders in each place value.

5th Grade Module 2 – Lesson 23

Divide Decimals

6 tens ÷ 3 =

Say the division

sentence in unit form.

Six tens divided by three equals

two tens.

5th Grade Module 2 – Lesson 23

Divide Decimals

6 tenths ÷ 3 =

Say the division

sentence in unit form.

Six tenths divided by three

equals two tenths

5th Grade Module 2 – Lesson 23

Divide Decimals

6 hundredths ÷ 3 =

Say the division

sentence in unit form.

Six hundredths divided by

three equals two

hundredths.

5th Grade Module 2 – Lesson 23

Divide Decimals

9 thousandths ÷ 3 =

Say the division

sentence in unit form.

Nine thousandths

divided by three equals three thousandths.

5th Grade Module 2 – Lesson 23

Divide Decimals

9 tenths ÷ 3 =

Say the division

sentence in unit form.

Nine tenths divided by three

equals three tenths.

5th Grade Module 2 – Lesson 23

0.1Say the number

as a decimal.

One tenth

Rename Tenths and Hundredths

5th Grade Module 2 – Lesson 23

0.2Say the number

as a decimal.

two tenths

Rename Tenths and Hundredths

5th Grade Module 2 – Lesson 23

0.3Say the number

as a decimal.

three tenths

Rename Tenths and Hundredths

5th Grade Module 2 – Lesson 23

0.8Say the number

as a decimal.

eight tenths

Rename Tenths and Hundredths

5th Grade Module 2 – Lesson 23

0.9Say the number

as a decimal.

nine tenths

Rename Tenths and Hundredths

5th Grade Module 2 – Lesson 23

10 tenths = 11tenths =19 tenths=20 tenths =30 tenths =80 tenths =90 tenths =100 tenths =200 tenths =

Write the number.

Rename Tenths and Hundredths

5th Grade Module 2 – Lesson 23

1hundredth = 2 hundredths =3 hundredths=8 hundredths =9 hundredths =100 hundredths =200 hundredths =900 hundredths =1000 hundredths =

Write the number.

Rename Tenths and Hundredths

5th Grade Module 2 – Lesson 23

Divide by Two Digit Numbers

650 ÷ 16÷ 20 60

0 30

Estimate Standard Algorithm

650 ÷ 16

650164

-64

R10

10

0

- 0 10

5th Grade Module 2 – Lesson 23

Divide by Two Digit Numbers

740 ÷ 32÷ 30 72

0 24

Estimate Standard Algorithm

740 ÷ 32

74032 2

-640100

R4

- 964

3

5th Grade Module 2 – Lesson 23

Divide by Two Digit Numbers

890 ÷ 27÷ 30 90

0 30

Estimate Standard Algorithm

890 ÷ 27

890273

-81

R26

80

2

-54 26

5th Grade Module 2 – Lesson 23

Application Problem

The rectangular room measures 224 square feet. One side of the room is 14

feet long. What is the perimeter of the room?

Solution on next slide…

Hint…This is a two-step problem.

5th Grade Module 2 – Lesson 23

Solution

14 16224

-14 84224 ft2

-84 0

14

?(16 x 2) + (14 x 2) =

32 + 28 = 60 ft perimeter

5th Grade Module 2 – Lesson 23

Concept Development

6,247 ÷ 29 Let’s first use rounding to find an estimated quotient!

6247 ÷ 17≈ 6000 ÷ 30 ≈ 200

Standard Algorithm

6247

29Can we divide 6 thousands

by 29?Not without regrouping!

So let’s work with 62 hundreds!Divide 62 hundreds by 29. We can use estimation to help us find the closest

quotient.Think…

60 hundreds ÷ 30 = 2 hundreds

2

58

So our quotient is about 2 hundred. Let’s record a 2

in the hundreds place.

On your whiteboard solve2 hundred x 29 =

We will record it under the dividend

How many hundreds are remaining?62 hundred – 58 hundred

4 hundredLet’s record that on the standard

algorithm

-___ 4

5th Grade Module 2 – Lesson 23

Concept Development

6,247 ÷ 29

Standard Algorithm

6247

292

58-___ 4

Let’s decompose (regroup) the 4 hundreds into 40 tens plus the 4 tens

still left in the dividend.

That will give us 44 tens

We can bring down the 4 and write it next to the 4 in the hundreds place.

4

Now we must divide 44 tens by 29.

Estimate 44 ÷ 29 on your white board

The best estimation to use is30 tens ÷ 20 = 1 ten

So we can put a 1 in the tens place in the quotient.

1

What is 1 ten X 29 =

29

How much is still remaining?44 – 29 = ___

-___ 15

Can we divide again or must we decompose?

We can’t divide again because the reminder is less

than the divisor.We need to decompose 15 tens into 150 ones, plus the

7 ones in our whole, to make 157 ones.

7

Now we have 157 ones divided by 29.

Estimate 157 ÷ 29

150 ÷ 30 = ___5Let’s finish up the problem by using 5.

Find 5 x 29 then find the remainder.

145

5

145-___ 12

What does the 12 remaining mean?

Check the answer on your white board.

5th Grade Module 2 – Lesson 23

Let’s do this one together. First, estimate the quotient.

Solution (use ink tools):

4,289 ÷ 52

5th Grade Module 2 – Lesson 23

Work with your partner to solve for the quotient. Estimate, solve, and check.

Solution (use ink tools or display student work):

6,649 ÷ 63

5th Grade Module 2 – Lesson 23

Solve this problem independentlyEstimate, solve, and check.

Solution (use ink tools or display student work):

3,164 ÷ 45

5th Grade Module 2 – Lesson 23

Get Ready to Complete theProblem Set on Your Own!

Complete Pages 2.F.55 & 2.F.56You will have 15-20 minutes to work.

Try your Best!

5th Grade Module 2 – Lesson 23

LET’S DEBRIEF• What pattern did you notice between 1(e) and 1(f)? Since the

quotient was 70 with remainder of 14 for both problems, does that mean the two division expressions are equal? Does the remainder of 14 represent the same thing?

• When dividing did your estimate need adjusting at times? When? What did you do in order to continue dividing?

• Compare your quotients in Problem 1. What did you notice in Problem 1 (a, b, and c)? Will a four-digit total divided by a two-digit divisor always result in a three-digit quotient? How does the relationship between the divisor and the whole impact the number of digits in the quotient?

5th Grade Module 2 – Lesson 23

EXITTICKETPage 2.F.57