Muliplication of Fractions Class 9 June 30, 2011 Common Core Leadership in Mathematics Project

Muliplication of Fractions

Class 9

June 30, 2011

Common Core Leadership in Mathematics Project

Common Core Leadership in Mathematics Project, University of Wisconsin-Milwaukee, Summer Institute 2011

Learning Intentions

We are learning to Develop strategies related to multiplying fractions. Understand how estimation should be an integral part of fraction

computation development. Read and interpret the cluster of CCSS standards related to

multiplication of fractions.

We will know we are successful when we can Justify our thinking when multiplying fractions using concrete

models and estimation strategies. Clearly explain and provide examples for specific CCSS standards


Big Ideas for Multiplication and Division of Fractions

Multiplication and division of fractions are among the most complicated fraction concepts that elementary students encounter.

Instructional opportunities that students encounter should include the meaning of multiplication and division on a range of situations and build procedural fluency with understanding.


Launch: Building on What We Know

What do you know about multiplication / division of whole numbers?

As a table group, make a list of what students have learned as they interact with multiplication and division problems.

Are they all true for fractions?


The Importance of Models

Researchers indicate that teachers need knowledge of concrete models to help students transition from multiplication of whole numbers to multiplication of fractions. (Fendel, 2000)


Thinking in Whole Numbers

3 X 4 = 12

Write a word problem for this equation

What does each number mean?


Some Stories

Solve these problems individually. Use a visual model to record and then discuss your thinking with the group. Then write an equation.

There are 15 cars in Derek’s toy car collection. Two-thirds of the cars are red. How many red cars does Derek have?

Frelesha has 11 cookies. She wants to share them with her three friends. How many cookies will Frelesha and each of her friends get, if they share them equally?

Jason filled 5 glasses with 2/3 liter of soda in each glass. How much soda did Jason use?


More Stories

Solve these problems individually. Use a model to record and then discuss your thinking with your group. Write an equation for each problem.

You have of a pizza left. If you give of the left-over pizza to your brother, how much of a whole pizza will your brother get?

Someone ate of a cake, leaving only . If your brother eats 2/3 of the cake that is left, how much of a whole cake will your brother eat?

4

3

3

1

€

1

10

€

9

10


And Still More Stories

Draw pictures to solve these problems. Do not use a computational algorithm. Write an equation.

• Joe had 2/3 of the lawn left to cut. After lunch, he cut 3/ 4 of the lawn he had left. How much of the whole lawn did Joe cut after lunch?

• The zookeeper had a huge bottle of the animals’ Zoo Cola. The monkey drank 1/5 of the bottle. The zebra drank 2/3 of what was left. How much of the bottle of Zoo Cola did the zebra drink?


Multiplying with Mixed Numbers

Determine the solution to these problems. Do not use a computational algorithm.

6 ½ x 4

2 ½ x 5 ¾


Revisiting Word Problems

Examine the five problems on the handout.

Which are story problems for 2/3 x 1/ 4 and which are not? Why?


Multiplication of Fraction Standards

4NF4a, 4NF4b, 5NF3, 5NF4, 5NF5

On your Standards Interpretation Sheet rephrase these standards and provide an example. Share with your partner.


Standards for Mathematical Practice

Documents

Muliplication of Fractions Class 9 June 30, 2011 Common Core Leadership in Mathematics Project