Decimal Multiplication and Division

Decimal Multiplication and Division

Solve Decimal Problems Using Mental Math

Opening

Solve Decimal Problems Using Mental Math

  • Solve these problems using mental math.

0.3 × 7

3 × 0.7

0.3 × 0.7

0.03 × 0.7

21 ÷ 0.7

2.1 ÷ 3

2.1 ÷ 0.3

210 ÷ 0.7

  • Compare your solutions with those of your classmates.
  • Discuss the strategies you used to find the solutions.

Math Mission

Opening

Identify diagrams and solutions for word problems involving decimal operations.

Match Solutions and Diagrams

Work Time

Match Solutions and Diagrams

Work with a partner.

  • Take turns matching a problem card, diagram card, and solution card.
  • Explain to your partner how you know that the cards match.
  • Your partner should either agree with your explanation or challenge it if your explanation is not correct, clear, and complete.
  • For each matched set, explain what the solution card represents.

Ask yourself:

  • Think about the operations you would use to solve the problem, and then find a diagram card that shows that operation.
  • Think about what the problem asks for as you decide what the solution card represents.

Prepare a Presentation

Work Time

Prepare a Presentation

Choose one of your matches. Explain why you think the cards match.

Challenge Problem

  • Write a word problem with decimals that requires using two different operations to solve.

Make Connections

Performance Task

Ways of Thinking: Make Connections

Take notes about your classmates' approaches to matching the cards.

As your classmates present, ask questions such as:

  • Can you explain the strategies you used to match the cards?
  • How does the diagram on the diagram card reflect the problem?
  • How does the diagram show the parts of the problem and the solution?

Operations With Decimals

Formative Assessment

Summary of the Math: Operations With Decimals

Write a summary about solving problems with decimals.

Check your summary.

  • Do you compare how you perform operations with decimals to how you perform operations with whole numbers?
  • Do you discuss how estimation helps you operate with decimals?

Reflect On Your Work

Work Time

Reflection

Write a reflection about the ideas discussed in class today. Use the sentence starters below if you find them to be helpful.

Ways that performing operations with decimals is like performing operations with whole numbers are …

Ways that performing operations with decimals is different from performing operations with whole numbers are …