Lesson Estimating Quotients 5-22

Mathematics Grade 5

Module: Division

Do Now

Whiteboard.

A garden has 1600 flowers that need to be planted equally into 40 rows.
How many flowers will be in each row?

Learning Objective:

SWBAT

SWBAT estimate to divide dividends with two-digit divisors. 5.3A

Demonstration of Learning:

SW estimate to divide dividends with two-digit divisors correctly in at least 4 out

of 5 problems.

5.3(A) estimate to determine solutions to mathematical and real‐world problems involving addition, subtraction, multiplication, or division

Module2 | Topic F | Lesson21

Division

Lesson Vocabulary

Division

Dividend

Divisor

The term “division” means to split into equal
parts or groups. The division splits everything
equally.

The dividend is the number that is being
divided up.

The divisor is the number you are dividing
by or how many equal groups you will
create.

Quotient

Remainder

Multiples

A result obtained by dividingone quantity by
another.

A part of something that is left over.

10, 20. 30, 40, 50, 60, 70

a number that can be divided by another number
without a remainder.
10, 20, 30, 40, 50, 60 … are multiples of 10

SWBAT estimate to divide quotients with two-digit divisors.

54

6

9

0

Multiples of 10

Review:
Divide by

Multiples of 10, 100, and 1,000

Divide by Multiples of 10, 100, and 1,000

Whiteboard

15,000 ÷ 300

SWBAT estimate to divide quotients with two-digit divisors.

Let’s Review!

15,000 ÷ 3 ÷ 100
15,000 ÷ 100= 150

150 ÷ 3= 50

SWBAT estimate to divide quotients with two-digit divisors.

​Now that we've reviewed, open a new tab and get ready for a warm-up quiz on Quizizz!

Round to the Nearest Ten

Round to the Nearest Ten

Whiteboard

21 ≈ ____

SWBAT estimate to divide quotients with two-digit divisors.

Round to the Nearest Ten

Whiteboard

37 ≈ ____

SWBAT estimate to divide quotients with two-digit divisors.

Round to the Nearest Ten

Whiteboard

Round: 54 ≈ ____

Use the vertical number line if you need it.

SWBAT estimate to divide quotients with two-digit divisors.

Round to the Nearest Ten

Whiteboard

65 ≈ ____

SWBAT estimate to divide quotients with two-digit divisors.

Round:

Use the vertical number line if you need it.

Round to the Nearest Ten

Whiteboard

25 ≈ ____

SWBAT estimate to divide quotients with two-digit divisors.

Round:

Use the vertical number line if you need it.

Concept Development

Concept Development

Oral Response

Problem 1

402 ÷ 19 = ____

SWBAT estimate to divide quotients with two-digit divisors.

The dividend is the number
that is being divided up.

What is the
dividend in this

problem?

The dividend in this problem is_______.

Concept Development

Whiteboard/ Oral Response

Problem 1
402 ÷ 19 = ____

SWBAT estimate to divide quotients with two-digit divisors.

And, What is
the divisor?

Now, let’s round the
divisor first.
What is 19 rounded
to the nearest ten?

The divisor in this problem is _____.

Concept Development

Response Card/ Think-Pair -Share

Problem 1

402 ÷ 19 = ____

≈ ____ ÷ 20

SWBAT estimate to divide quotients with two-digit divisors.

Share your ideas with

your partner.

We need to round
our whole,402, to a
number that can
easily be divided by
20.

Let’s share your ideas!

I think we can round our whole, 402 to _______ because_____.

Concept Development

Whiteboard/ Oral Response

Problem 1

SWBAT estimate to divide quotients with two-digit divisors.

402 ÷ 19 ≈ 400 ÷ 20

Now, Let’s solve

Estimated quotient is______.

How did estimating help solve the division problem?

Concept Development
Whiteboard

Problem 2

Take out your whiteboard, and let’s estimate the quotient of the
following equation:

149 ÷ 71 = ____

SWBAT estimate to divide quotients with two-digit divisors.

Multiple Choice

What's the first step to estimating the quotient?

• Look at my neighbor's paper

• Daydream about summer

• Round the divisor and dividend and/or use compatible numbers

• Stare at the screen

Concept Development

Whiteboard/ Oral Response

Yes, we will round our divisor to 70!

149 ÷ 71 = ____

≈ ____ ÷ 70

SWBAT estimate to divide quotients with two-digit divisors.

When we are rounding
for division , we look for
a number that is a
multiple (compatible number)
of the divisor.
Count with me by
seventies.

Let’s count!
70, 140, 210, 280, 350

We are rounding to the
nearest multiple of 70.
149 is closest to which
multiple of 70?

Concept Development

Whiteboard / Oral Response

SWBAT estimate to divide quotients with two-digit divisors.

Therefore, our estimation will be:

➢ 140 divided by 70 is the same as 14 divided by what? Say the

division sentence

Let’s prove it!

Our estimated quotient = 2

Concept Development

Whiteboard/ T-P-S

Problem 3

Let’s estimate the next quotient:
427 ÷ 58 = ____

SWBAT estimate to divide quotients with two-digit divisors.

Work with a partner to
estimate the divisor and
the dividend.

Then, estimate the
quotient…

Let’s review:
What’s the
estimated divisor?

Did you count by sixties and stop when
we find a multiple near 427?

Problem 4
293 ÷ 42 = ____

SWBAT estimate to divide quotients with two-digit divisors.

➢

➢

➢

Work with your partner.

Concept Development

Whiteboard/ T-P-S

Problem 5
751 ÷ 93 = ____

SWBAT estimate to divide quotients with two-digit divisors.

➢

➢

➢

Whiteboard/ T-P-S

​Work with your face partner:

SW estimate to divide quotients with two-digit divisors correctly in at

least 4 out of 5 problems.