Loading...

PPT – Addition and Subtraction of Fractions Part 1 PowerPoint presentation | free to download - id: 64742d-OTQxZ

The Adobe Flash plugin is needed to view this content

Addition and Subtraction of Fractions Part 1

- Class 3
- October 9, 2012

Homework Discussion

- Discuss your response to last weeks homework as

a table group. - Read a quote you chose from the reading.
- Why was this an important idea?

- Standards for Mathematical Practice

(No Transcript)

Math Practices in Action

- Reflect back to last weeks activities for

comparing and ordering. - Choose two Standards for Mathematical Practice

that were evident in that work. How were they

evident? Be specific.

- An Overview of the Fraction Standards

Common Core State Standards for Fractions

Grades 1-6

- As you read the fractions standards,
- Highlight the word Understand.
- Highlight the words visual model(s).
- As a table, discuss the fraction progressions

that you found by examining these standards.

- Addition of Fractions

Learning Intentions

- We are learning to
- Develop operation sense related to addition of

fractions. - Understand how estimation should be an integral

part of fraction computation development. - Read and interpret the cluster of CCSS standards

related to addition/subtraction of fractions - We will know we are successful when we can
- Justify our thinking when adding and subtracting

fractions using concrete models and estimation

strategies. - Clearly explain and provide examples for specific

CCSS standards

Big Ideas for Addition and Subtraction of

Fractions

- Fraction addition and subtraction concepts build

from and are dependent upon - Foundational part-to-whole ideas
- Equivalence ideas
- Magnitude ideas
- Procedural fluency and conceptual understanding

work together to deepen student understanding of

fraction addition and subtraction.

Launch Building on What We Know

- Use a model to answer this
- question
- There are some candies in a dish.
- 2/5 of the candies are chocolate.
- 3/10 of the candies are peppermint.
- Are there more chocolate or peppermint candies?

Using Estimation

- Aunt Sally has a jar that holds one cup of

liquid. Her salad dressing recipe calls for - 2/3 cup of oil
- 1/8 cup of vinegar
- 1/2 cup of juice
- Is the jar large enough to hold all the oil,

vinegar and juice?

Exploring Addition (Subtraction) of Fractions

- Choose a target number from this set that is less

than 1 or more than 1. - Make a model of that number using your fraction

strips to serve as a reference. - Using your fraction strips find combinations to

represent your target number. - Start with combinations of 2 fractions, then 3,

then 4, etc. - Record your combinations. Also record any

conjectures your group makes as you work on the

task. - If you feel that you have explored all

combinations for your first target number, pick a

second one and do subtraction.

Example of target less than 1

Addition Fraction Combinations Debrief

- What patterns emerged as you made your

combinations? - What ideas about addition of fractions surface
- as you engaged in these explorations?
- How did the fraction strip model support your

thinking?

Connections to Standards 4.NF.3a, 4.NF.3b and

5.NF.1

- 1. Read these standards, highlighting important

words and phrases. - 4.NF.3 Understand a fraction a/b with a gt 1 as a

sum of fractions 1/b. - a. Understand addition and subtraction of

fractions as joining and separating parts

referring to the same whole. - b. Decompose a fraction into a sum of fractions

with the same denominator in more than one way,

recording each decomposition by an equation.

Justify decompositions, e.g., by using a visual

fraction model. Examples 3/8 1/8 1/8 1/8

3/8 1/8 2/8 2 1/8 1 1 1/8 8/8 8/8

1/8. - 5.NF.1 Add and subtract fractions with unlike

denominators (including mixed numbers) by

replacing given fractions with equivalent

fractions in such a way as to produce an

equivalent sum or difference of fractions with

like denominators. For example, 2/3 5/4 8/12

15/12 23/12. (In general, a/b c/d (ad

bc)/bd.) - 2. In your group, discuss highlighted key ideas

in this standard and questions you may have about

these standards. - 3. Work as a group to cite three specific

examples of how the previous activity made sense

of these standards.

NF Progression Document

- Study the sections, diagrams, and margin notes on

Adding and Subtracting Fractions. - Read Grade 4, page 6.
- Read Grade 5, page 10.
- Highlight important words and phrases, and note

surprising ideas or questions raised. - In particular, note how the standards

progression grows from grade 4 to grade 5 - In your group, discuss highlighted key ideas and

your questions about them.

Learning Intentions

- We are learning to
- Develop operation sense related to addition of

fractions. - Understand how estimation should be an integral

part of fraction computation development. - Read and interpret the cluster of CCSS standards

related to addition/subtraction of fractions

Success Criteria

- We will know we are successful when we can
- Justify our thinking when adding and subtracting

fractions using concrete models and estimation

strategies. - Clearly explain and provide an example for

specific CCSS standards.