Place Value, Rounding, Addition, and Subtraction

Lesson 19

Math

Unit 1

4th Grade

Lesson 19 of 19

Objective


Solve multi-step word problems involving addition and subtraction, using rounding to assess the reasonableness of answers.

Common Core Standards


Core Standards

  • 4.NBT.B.4 — Fluently add and subtract multi-digit whole numbers using the standard algorithm.
  • 4.OA.A.3 — Solve multistep word problems posed with whole numbers and having whole-number answers using the four operations, including problems in which remainders must be interpreted. Represent these problems using equations with a letter standing for the unknown quantity. Assess the reasonableness of answers using mental computation and estimation strategies including rounding.

Foundational Standards

  • 3.NBT.A.2
  • 3.OA.D.8

Criteria for Success


  1. Make sense of a three-act task and persevere in solving it (MP.1). 
  2. Solve two- and multi-step word problems involving addition and subtraction (MP.4).
  3. Represent word problems using equation(s) with a letter standing for the unknown quantity (see Tips for Teachers) (MP.2).
  4. Assess the reasonableness of answers by choosing a place to round the given values to, rounding them, and using those to compute the solution or by using the relationship between addition and subtraction to check answers (MP.1).

Tips for Teachers


  • As mentioned in Lessons 15 and 18, it isn’t especially clear whether students are expected to interpret, understand, and/or write one equation that represents a two- or multi-step word problem. As the Progressions state, “some problems might easily be represented with a single equation, and others will be more sensibly represented by more than one equation or a diagram and one or more equations” (OA Progression, p. 29). Thus, it is left to the teacher to decide what “easily” and “sensibly” means for your students, and when to make the transition to representing some two- and multi-step word problems with one step of representation/one equation, which you could do here or wait for subsequent lessons and units to do so. As some general guidance, it seems reasonable to expect every student to be able to write an equation for all one-step problems, two-step problems where the unknown is isolated on one side of the equal sign in the equation without needing to manipulate it, and some multi-step problems with the same parameters by the end of the year. For example, see #2 of Mathematics Common Core Sample Questions Grade 4, #5c of MCAS Spring 2016 Grade 4 Mathematics Test, and #11 of PARCC Math Spring 2017 Grade 4 Released Items.
  • This lesson provides an opportunity to connect two domains in the grade, 4.OA and 4.NBT, since students will be solving multi-step word problems involving addition and subtraction within 1,000,000 and assess the reasonableness of their answers using rounding, thus connecting standards 4.OA.3, 4.NBT.3, and 4.NBT.4.
  • Let students work on each problem on the Problem Set independently and circulate to see whether students are solving correctly. If not, come back together to discuss how/what to draw on a tape diagram, then allow them to try again on their own. Encourage students to use a strategy of their choice to assess the reasonableness of their solution.
Fishtank Plus

Unlock features to optimize your prep time, plan engaging lessons, and monitor student progress.

Anchor Tasks


Problem 1

Act 1: Look at the image below and answer the questions that follow. 

a.   What do you notice? What do you wonder?

b.   How many pieces of candy are there? Make an estimate.

Guiding Questions

Create a free account or sign in to access the Guiding Questions for this Anchor Problem.

References

Photo: Untitled by @julianasteiner (W Magazine)

Problem 2

Act 2: Use the following information to determine how many pieces of candy there are after the third month.

  • There were 15,750 pieces of candy at the beginning of the show, which ran for three months.
  • In the first month, 4,116 pieces were eaten.
  • 1,478 fewer pieces were eaten in the second month than in the first month. 
  • 1,060 more pieces were eaten in the third month than in the second month.

Guiding Questions

Create a free account or sign in to access the Guiding Questions for this Anchor Problem.

Problem 3

Act 3: There were 5,298 pieces left at the end of the show. Was your answer reasonable? Why or why not?

Guiding Questions

Create a free account or sign in to access the Guiding Questions for this Anchor Problem.

Problem Set


Answer Keys

Unlock the answer keys for this lesson's problem set and extra practice problems to save time and support student learning.

Discussion of Problem Set

  • Look at #3. How did drawing a double tape diagram help you to visualize the problem?
  • Why is there more than one right way to solve, for example, #5?
  • How are the problems alike? How are they different?
  • How was your solution the same and different from those that were demonstrated by your peers?
  • Did you see other solutions that surprised you or made you see the problem differently?
  • Why is it helpful to assess for reasonableness after solving?
  • How were the tape diagrams helpful in estimating to test for reasonableness? Why is that?

Target Task


In 2018, there were 13,910 McDonald’s restaurants, 7,205 fewer Wendy’s restaurants than McDonald’s, and 625 more Burger King restaurants than Wendy’s in the United States.

a.   How many of all three restaurants were there in all in 2018? Show or explain your work. 

b.   Assess the reasonableness of your answer.

Student Response

Create a free account or sign in to view Student Response

Additional Practice


The Extra Practice Problems can be used as additional practice for homework, during an intervention block, etc. Daily Word Problems and Fluency Activities are aligned to the content of the unit but not necessarily to the lesson objective, therefore feel free to use them anytime during your school day.

Extra Practice Problems

Answer Keys

Answer keys for Problem Sets and Extra Practice Problems are available with a Fishtank Plus subscription.

Word Problems and Fluency Activities

Word Problems and Fluency Activities

Help students strengthen their application and fluency skills with daily word problem practice and content-aligned fluency activities.

icon/arrow/right/large copy

Lesson 18

Lesson Map

A7CB09C2-D12F-4F55-80DB-37298FF0A765

Topic A: Place Value of Multi-Digit Whole Numbers

Topic B: Reading, Writing, and Comparing Multi-Digit Whole Numbers

Topic C: Rounding Multi-Digit Whole Numbers

Topic D: Multi-Digit Whole-Number Addition and Subtraction

Request a Demo

See all of the features of Fishtank in action and begin the conversation about adoption.

Learn more about Fishtank Learning School Adoption.

Contact Information

School Information

What courses are you interested in?

ELA

Math

Are you interested in onboarding professional learning for your teachers and instructional leaders?

Yes

No

Any other information you would like to provide about your school?

Effective Instruction Made Easy

Effective Instruction Made Easy

Access rigorous, relevant, and adaptable math lesson plans for free