DOC

# Addition and Subtraction of Fractions

By Laura Campbell,2014-04-30 23:50
11 views 0

Subtracting Fractions

January MTL Meeting

January 20 & 28

Marshall Complex

Core Content Development Team

DeAnn Huinker

Connie Laughlin

Kevin McLeod

Mary Mooney

Beth Schefelker

Melissa Hedges

Assisting MTLs

Frelesha LeFlore

Cecile Labecki

Learning Intentions:

; Develop “operation sense” related

fractions.

; Understand how estimation should

be an integral part of fraction

computation development.

Success Criteria:

At the end of this session you will be able to:

and subtracting fractions using

concrete models and estimation

strategies.

Types of Rational Numbers:

; Part-whole comparisons

; Quotients

; Operators

; Ratios and Rates

; Measurement

For each expression below…

(1) Estimate the sum and the difference for the expressions below. (2) Justify how you know your estimate is in the ballpark.

49/99 11/34 16/25 + 9/14

Background on Fraction Computation

; What ideas from the reading support

the work we’ve been engaged in

during the past 2 sessions around

fractions?

From:

Van de Walle, J. & Lovin H. (2006). Teaching Student Center Mathematics:

Grades 3-5. pp. 160-161. New York: Pearson Education.

Three Models Used to

Work With Fractions

Set model (Mariah's Kittens)

Linear model (Taking a Run)

1 mile 2 miles 3 miles 4 miles

Finding ? of 4 miles

Area Model (Spaghetti Problem)

? ? ? ?

4 packages of meat each weighing ? lbs

Folding Fraction Strips

Fold fraction strips to represent the following:

; one whole ; eighths

; halves ; thirds

; fourths ; sixths

As you fold, discuss with your partner how you know that your fraction strips are accurate.

Folding fraction strips is so time consuming. Why do it?

Turn and talk:

What was the benefit of folding

In what way would the cognitive

demand be affected if we were to

hand you a pre-printed set of

strips?

Exploring Operation Sense Using

Benchmark Fractions

Using your fraction strips, work through the following and have several examples for each:

; If you add 2 fractions and the sum is greater

than ?, what can you say about the fractions?

; If you add 2 fractions and the sum is greater

than 1, what can you say about the fractions?

; If you add 2 fractions, and the sum is more than

1 ?, what can you say about the fraction?

What conversations did you have with your partner that helped to develop a