Overview

Lesson 5 of 5 in the unit Mastering Decimal Operations
Grade Level: 5th Grade
Duration: 45 minutes
Class Size: 23 students

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Standards Alignment

CCSS.MATH.CONTENT.5.NBT.B.7
Perform operations with multi-digit whole numbers and with decimals to hundredths.

• 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.

CCSS.MATH.PRACTICE.MP1
Make sense of problems and persevere in solving them.

CCSS.MATH.PRACTICE.MP3
Construct viable arguments and critique the reasoning of others.

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Learning Objectives

By the end of this lesson, students will be able to:

• I can solve word problems involving addition, subtraction, multiplication, and division of decimals to the hundredths place.
• I can explain the strategy I used to solve a decimal word problem.
• I can check my work for accuracy using estimation or inverse operations.

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Success Criteria

Students will be successful if they can:

• Identify key information and operation(s) needed in decimal word problems.
• Accurately solve decimal operations within real-world contexts.
• Communicate how they solved a problem in their own words.
• Use estimation or the inverse operation to verify their answer.

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Materials Needed

• Whiteboard and markers
• Decimal word problem task cards (prepared in advance)
• Individual whiteboards or paper for working out problems
• Calculators (for students who need it as a scaffold)
• Dyslexia-friendly word problem printouts (clear font, larger spacing)
• Challenge problem worksheet for advanced learners
• Answer key handout for guided correction

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Lesson Procedure

1. Introduction (5 minutes)

I do - Teacher models applying decimal operations to solve a word problem.

• Write a decimal word problem on the board (example below).
• Think aloud while identifying key info, choosing operations, solving, and checking the answer.
• Problem example:
  “Sarah bought 3.25 pounds of apples at $2.40 per pound. How much did she pay in total?”
• Show step-by-step solution: multiply 3.25 x 2.40 = 7.80.
• Emphasize identifying keywords like “total,” “per pound,” etc.

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2. Guided Practice (We Do) (15 minutes)

We do - Students and teacher solve 2-3 word problems together.

• Present 2 word problems on screen or whiteboard.
• Call on students to suggest steps and operations.
• Work through problems together, writing solutions step-by-step.
• Encourage students to explain their reasoning aloud.
• Have students check answers using estimation (rounding decimals) or inverse operations.

Problem examples:

• “Jacob bought 5.75 liters of juice. Each liter costs $1.60. How much did he spend?” (Multiplication)
• “A cake recipe calls for 2.5 cups of sugar. Samantha used 0.75 cups less than the amount needed. How much sugar did she use?” (Subtraction)

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3. Independent Practice (You Do) (15 minutes)

You do - Students solve 3-4 decimal word problems on their own or in pairs.

• Hand out task cards or worksheets with 3-4 word problems of increasing difficulty.
• Students work on individual whiteboards, paper, or laptops for EL support.
• Teacher circulates to scaffold and assist students who need help.

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4. Differentiation Strategies

• For students struggling with decimals:
  • Provide calculators or manipulatives (decimal grids or base-ten blocks).
  • Provide dyslexia-friendly worksheets with simplified language.
  • Offer extra time or break problems into smaller steps.
• For EL students:
  • Use visuals and bilingual vocabulary cards for math terms (add, subtract, multiply, divide).
  • Pair with a buddy for language support.
  • Read problems aloud and explain vocabulary prior to working.
• For advanced learners:
  • Provide extension problems that involve multi-step word problems, mixing all four operations.
  • Challenge them to create their own decimal word problems and explain solutions.

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5. Closure & Reflection (5 minutes)

• Invite several students to share how they solved a problem and the strategy they used.
• Review the I can statements and check off student understanding with thumbs up/down or exit tickets.
• Emphasize the importance of estimation and checking work to avoid mistakes.

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6. Homework / Extension (optional)

• Complete a set of 3 multi-step decimal word problems that require 2 operations.
• Advanced learners write their own word problems including decimals and exchange with a partner to solve.

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Step-by-Step Assignment Instructions

For each word problem:

1. Read the problem carefully. Underline or highlight important numbers and keywords.
2. Determine what operation(s) to use. Ask yourself if you need to add, subtract, multiply, or divide decimals.
3. Set up the calculation. Write the decimal operation clearly.
4. Solve the problem using your preferred method. Use paper, drawings, or a calculator if allowed.
5. Estimate to check your answer. Round numbers to the nearest whole number and see if your answer makes sense.
6. Write a sentence explaining how you solved the problem. This helps practice communicating math thinking.

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Answer Key (Sample Problems from Lesson)

1. Sarah’s apples: 3.25 × 2.40 = 7.80 total dollars
2. Jacob’s juice: 5.75 × 1.60 = 9.20 total dollars
3. Samantha’s sugar: 2.5 – 0.75 = 1.75 cups used

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Additional Teacher Tips

• Use visual models like decimal grids or place value charts during explanation.
• Encourage student collaboration during “We Do” to build confidence.
• Use sentence frames for ELs: “The problem asks me to ___, so I will ___.”
• Refer to math vocabulary frequently and in context.
• Celebrate perseverance in problem-solving with praise or certificates.

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This detailed, scaffolded approach ensures all students engage meaningfully with decimal word problems and build confidence applying decimal operations in real-life contexts — perfectly aligned with the Common Core standards!