October 8, 2024

October 8, 2024

Grade 3 Mathematics

Unit 5: Two-Step Addition and Subtraction Problem Solving

Lesson 1: Represent and Solve Addition and Subtraction Problems
(Estimate)

LO: SWBAT represent, estimate, or solve
two-step addition and subtraction problems.

DOL: Given a set of problems, students will
correctly represent, estimate, or solve two-step
addition and subtraction problems in a least 4
out of 5 problems.

MATH. 3.5 (A) represent one‐ and two‐step problems involving addition and subtraction of whole numbers to 1,000 using pictorial models, number lines, and
equations.

MATH 3.4 (B) round to the nearest 10 or 100 or use compatible numbers to estimate solutions to addition and subtraction problems.

MATH 3.4 (A) solve with fluency one‐step and two‐step problems involving addition and subtraction within 1,000 using strategies based on place value,
properties of operations, and the relationship between addition and subtraction

4

Academic Vocabulary

5

Sum
(add)

Difference
(subtract)

Equation

(needs equal sign)

Strip Diagram

(total and parts)

Unknown Term

(missing/amber alert)

Estimate

(round 10 or 100)

15 + 20 = 35

35 - 15 = 20

35 - 15 = 20

35

15

?

15 + = 35

15 20

35 40

​?

?

6

Inspiration Partnership Team Vector by Vecteezy.com

Today, we will begin learning how to represent,
estimate, and solve two-step word problems
involving addition and subtraction.

Essential Question

7

Image by OpenClipart-Vectors from Pixabay

I can represent a two-step addition
and subtraction problem by …..

How can you represent
a two-step addition
and subtraction word
problem?

Multiple Choice

There are 228 girls and 263 boys at the museum. After lunch, 117 of the children go home. About how many children are still at the museum?

• 370

• 610

• 360

• 590

Multiple Choice

Quinn earned $225 mowing lawns during the summer. She earned $156 helping her grandmother work on the farm. She spent $45 on a baseball bat. Which equation can be used to find the amount of money Quinn has in all?

• A

• B

• C

• D

8

A factory makes 400 refrigerators every day. The factory makes 125 more stoves per day than refrigerators. Which strip diagram can be be used to find the total number of refrigerators and stoves the factory makes in one day?

A.

B.

C.

D.

?

400

400

125

400

125

?

?

400

125

400

400

125

?

Draw strip diagram here

Write the Equation here

Multiple Choice

A factory makes 400 refrigerators every day. The factory makes 125 more stoves per day than refrigerators. Which strip diagram can be be used to find the total number of refrigerators and stoves the factory makes in one day?

9

Travis saved $700 to redecorate his house. He purchased a lamp for $75 and a couch for $378. He also wants to purchase a table. Which set of equations can be used to determine how much money Travis has left to spend on a table?

A.

$378 + $75 = $453

$453 + $700 =

B.

$378 – $75 = $303

$700 – $303 =

C. $700 – $378 = $322

$322 + $75 =

D. $75 + $378 = $453

$700 – $453 =

Draw strip diagram here

Draw

Travis saved $700 to redecorate his house. He purchased a lamp for $75 and a couch for $378. He also wants to purchase a table. Which set of equations can be used to determine how much money Travis has left to spend on a table?

(Draw the strip diagram and submit)

9

Travis saved $700 to redecorate his house. He purchased a lamp for $75 and a couch for $378. He also wants to purchase a table. Which set of equations can be used to determine how much money Travis has left to spend on a table?

A.

$378 + $75 = $453

$453 + $700 =

B.

$378 – $75 = $303

$700 – $303 =

C. $700 – $378 = $322

$322 + $75 =

D. $75 + $378 = $453

$700 – $453 =

Draw strip diagram here

Multiple Choice

Travis saved $700 to redecorate his house. He purchased a lamp for $75 and a couch for $378. He also wants to purchase a table. Which set of equations can be used to determine how much money Travis has left to spend on a table?

10

Ms. Brown knows there are 204 third graders in the gym for field-day activities.
There are 68 students in the golf line, and seventy-two students at the table tennis event. The rest of the students are in the relay race lines. How many students are in the relay race lines?

Draw strip diagram here

Draw

Ms. Brown knows there are 204 third graders in the gym for field-day activities. There are 68 students in the golf line, and seventy-two students at the table tennis event. The rest of the students are in the relay race lines. How many students are in the relay race lines?

(Draw strip diagram)

10

Ms. Brown knows there are 204 third graders in the gym for field-day activities.
There are 68 students in the golf line, and seventy-two students at the table tennis event. The rest of the students are in the relay race lines. How many students are in the relay race lines?

Draw strip diagram here

Open Ended

Solve for the answer and type your sentence.

How many students are in the relay race lines?

Sentence stem: There are ___ students __ .

11

A food bank received cans of vegetables last week. It received 130 cans of corn. It received 148
more cans of beans than corn. How many cans of corn and beans did the food bank receive last week?

A.

308

B.

18

C.

408

D.

278

Draw strip diagram here

Write the Equation here

Multiple Choice

A food bank received cans of vegetables last week. It received 130 cans of corn. It received 148 more cans of beans than corn. How many cans of corn and beans did the food bank receive last week?

Draw Strip Diagram and equation

• A

• B

• C

• D

16

Recap

Do you agree with Ashley's equation?

Bay’s Department Store sold 200 pairs of sandals in one day. They sold 190 more pairs of sneakers than sandals.

Write an equation to determine the number of pairs of sandals and sneakers sold in one day.

I ________ with Ashley's equation because _____________.
(agree/disagree)

200 + 190 =

18

Demonstration of Learning

DOL:Given a set
of problems,
students will
correctly represent,
estimate, or solve
two-step addition
and subtraction
problems in a least
4 out of 5 problems

Learner Slides

19

Learner Slides