# Addition and Subtraction of Fractions/Decimals

## Objective

Solve two- and multi-step word problems involving addition and subtraction of decimals.

## Common Core Standards

### Core Standards

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• 5.NBT.B.7 — Add, subtract, multiply, and divide decimals to hundredths, using concrete models or drawings and strategies based on place value, properties of operations, and/or the relationship between addition and subtraction; relate the strategy to a written method and explain the reasoning used.

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• 4.OA.A.3

## Criteria for Success

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1. Make sense of a three-act task and persevere in solving it (MP.1).
2. Solve two- and multi-step word problems that involve the addition and subtraction of decimals (MP.4).
3. Assess the reasonableness of an answer to a word problem involving the addition and subtraction of decimals (MP.1).

## Tips for Teachers

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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 answer.

#### Fishtank Plus

• Problem Set
• Student Handout Editor
• Vocabulary Package

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### Problem 1

Act 1: Show the first 24 seconds of the following video from the 2016 Olympics (making sure students do not see the title of it) -

Who won the relay? By how much?

#### References

YouTube Video: “USA takes gold in Men's 4x100m Freestyle Relay”

USA takes gold in Men's 4x100m Freestyle Relay by is made available by YouTube under the Standard YouTube License. Accessed Feb. 11, 2018, 2:37 p.m..

### Problem 2

Act 2: Use the following information to solve -

 Nation Swimmers United States Caeleb Dressel (48.1) Michael Phelps (47.12) Ryan Held (47.73) Nathan Adrian (46.97) France Mehdy Metella (48.08) Fabien Gilot (48.2) Florent Manaudou (47.14) Jeremy Stravius (47.11)

### Problem 3

Act 3: Reveal the answer -

The United States won the race. They beat France's time by 0.61 seconds.

### Problem 4

Act 4 (the sequel) -

What was the leading team's time in minutes and seconds?

## Discussion of Problem Set

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• Look at #1b. I got 2.36 seconds. Is my answer reasonable? Why or why not? What mistake do you think I made?
• Look at #5. What did you get for the cost of the notebooks? What multiplication sentence can I write to describe this relationship? What do you notice about the factors and product?

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Lina brought $10 to the fair. • She spent$2.59 for cotton candy.
• She spent \$3.49 for a toy.

How much money did Lina have left?

#### References

Massachusetts Department of Elementary and Secondary Education Spring 2018 Grade 5 Mathematics TestQuestion #27

Spring 2018 Grade 5 Mathematics Test is made available by the Massachusetts Department of Elementary and Secondary Education. © 2017 Commonwealth of Massachusetts. Accessed Dec. 4, 2018, 2:38 p.m..

Modified by The Match Foundation, Inc.

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