Number and operations—fractions Develop understanding of

Subject
Unit 5
Middletown Public Schools
Mathematics Unit Planning Organizer
Mathematics - Number and Operations - Fractions
Grade
3
Reasoning about Fraction Comparisons and Equivalence
Duration
15 Instructional Days (+ 5 Reteaching/Extension Days)
Big Idea
Essential
Question
When comparing fractions look at both the size and number of parts.
What is an equivalent fraction?
How do I compare with different denominators?
Mathematical Practices
Practices in bold are to be emphasized in the unit.
1. Make sense of problems and persevere in solving them.
2. Reason abstractly and quantitatively.
3. Construct viable arguments and critique the reasoning of others.
4. Model with mathematics.
5. Use appropriate tools strategically.
6. Attend to precision.
7. Look for and make use of structure.
8. Look for and express regularity in repeated reasoning.
Domain and Standards Overview
Number and operations—fractions
Develop understanding of fractions as numbers
CC.3.NF.3 Explain equivalence of fractions in special cases, and compare fractions by reasoning about their size.
a. Understand two fractions as equivalent (equal) if they are the
same size, or the same point on a number line.
b. Recognize and generate simple equivalent fractions, e.g., 1/2 = 2/4, 4/6 = 2/3). Explain why the fractions are equivalent, e.g., by using a visual fraction model.
c. Express whole numbers as fractions, and recognize fractions that are equivalent to whole numbers. Examples: Express 3 in the form 3 = 3/1; recognize that 6/1 = 6; locate 4/4 and 1 at the same point
of a number line diagram.
d. Compare two fractions with the same numerator or the same denominator by reasoning about their size. Recognize that
comparisons are valid only when the two fractions refer to the same whole. Record the results of comparisons with the symbols >, =, or <, and justify the conclusions, e.g., by using a visual fraction mo del.
CC.3.G.2 Partition shapes into parts with equal areas. Express the area of each part as a unit fraction of the whole. For example, partition a shape into 4 parts with equal area, and describe the area of each part as 1/4 of the
area of the shape.
Grade 3 Unit 5 Reasoning about Fraction Comparison and Equivalence
March 2013
Priority and Supporting Common Core State Standards
Explanations and Examples
Bold Standards are Priority
3.NF.3. Explain equivalence of fractions in special cases, and
compare fractions by reasoning about their size.
a. Understand two fractions as equivalent (equal) if they are the
same size or the same point on a number line.
b. Recognize and generate simple equivalent fractions, e.g., 1/2 =
2/4, 4/6 = 2/3). Explain why the fractions are equivalent, e.g., by
using a visual fraction model.
3.NF.3. An important concept when comparing fractions is to look at the
size of the parts and the number of the parts. For example, 1/8 is smaller
than ½ because when 1 whole is cut into 8 pieces, the pieces are much
smaller than when 1 whole of the same size is cut into 2 pieces.
Examples:
Use fraction bars
1 2 4 2
 , 
2 4 6 3
c. Express whole numbers as fractions, and recognize fractions
that are equivalent to whole numbers. Examples: Express 3 in the
form 3 = 3/1; recognize that 6/1 = 6; locate 4/4 and 1 at the same
point of a number line diagram.
d. Compare two fractions with the same numerator or the same
denominator by reasoning about their size. Recognize that
comparisons are valid only when the two fractions refer to the same
whole. Record the results of comparisons with the symbols >, =, or <,
and justify the conclusions, e.g., by using a visual fraction model.
Use number lines
0
1
1/6
0
2/6
3/6
4/6
5/6
6/6
1
¼
2/4
¾
4/4
Students recognize when examining fractions with common
denominators, the wholes have been divided into the same number of
equal parts. So the fraction with the larger numerator has the larger
number of equal parts.
2 5

6 6
Grade 3 Unit 5 Reasoning about Fraction Comparison and Equivalence
March 2013
To compare fractions that have the same numerator but different
denominators, students understand that each fraction has the same
number of equal parts but the size of the parts are different. They can
infer that the same number of smaller pieces is less than the same number
of bigger pieces.
3 3

8 4
3.G.2. Partition shapes into parts with equal areas. Express the area
of each part as a unit fraction of the whole. For example, partition a
shape into 4 parts with equal area, and describe the area of each part
as 1/4 of the area of the shape
Concepts
Skills
What Students Need to Know
What Students Need to Be Able to Do
Equivalence of Fractions
Fractions
3.G.2. Given a shape, students partition it into equal parts, recognizing
that these parts all have the same area. They identify the fractional name
of each part and are able to partition a shape into parts with equal areas in
several different ways.
UNDERSTAND (as same size or same point on
number line)
RECOGNIZE (simple equivalent fractions)
GENERATE (simple equivalent fractions)
EXPLAIN (why fractions are equivalent using
visual models)
COMPARE (two with same numerator or
denominator by reasoning about size)
RECOGNIZE (comparisons are only valid when
referring to same whole)
RECORD (results of comparisons using >, =, <)
JUSTIFY (results of comparisons)
EXPRESS (whole numbers as fractions)
Grade 3 Unit 5 Reasoning about Fraction Comparison and Equivalence
March 2013
Bloom’s Taxonomy Levels
(drop down menu?)
2
2
2
2
4
2
1
5
2
2
Shapes
RECOGNIZE (when equivalent to whole
numbers)
PARTITION (into parts with equal areas)
EXPRESS (area of each part as a unit fraction of
the whole shape)
3
3
Learning Progressions
Prerequisite Skills
Standards
CC.3.NF.3 Explain equivalence of fractions in special
cases, and compare fractions by reasoning about their
size.
a. Understand two fractions as equivalent (equal) if they
are the same size, or the same point on a number line.
b. Recognize and generate simple equivalent fractions,
e.g., 1/2 = 2/4, 4/6 = 2/3). Explain why the fractions are
equivalent, e.g., by using a visual fraction model.
c. Express whole numbers as fractions, and recognize
fractions that are equivalent to whole numbers.
d. Compare two fractions with the same numerator or the
same denominator by reasoning about their size.
Recognize that
comparisons are valid only when the two fractions refer
to the same whole. Record the results of comparisons
with the symbols >, =, or <, and justify the conclusions,
e.g., by using a visual fraction model.
CC.3.G.2 Partition shapes into parts with equal areas.
Express the area of each part as a unit fraction of the
whole.
CC.2.OA.2 Fluently add and subtract within 20 using
mental strategies.2 By end of Grade 2, know from
memory all sums of two one-digit numbers.
CC.2.OA.3 Determine whether a group of objects (up to
20) has an odd or even number of members, e.g., by
pairing objects or counting them by 2s; write an equation
to express an even number as a sum of two equal
addends.
CC.2.OA.4 Use addition to find the total number of
objects arranged in rectangular arrays with up to 5 rows
and up to 5 columns; write an equation to express the
total as a sum of equal addends.
CC.2.G.3 Partition circles and rectangles into two, three,
or four equal shares, describe the shares using the words
halves, thirds, half of, a third of, etc., and describe the
whole as two halves, three thirds, four fourths. Recognize
that equal shares of identical wholes need not have the
same shape.
Acceleration
CC.4.NF.1 Explain why a fraction a/b is equivalent to a
fraction (n × a)/(n × b) by using visual fraction models,
with attention to how the number and size of the parts
differ even though the two fractions themselves are the
same size. Use this principle to recognize and generate
equivalent fractions.
CC.4.NF.3 Understand a fraction a/b with a > 1 as a sum
of fractions 1/b.a. Understand addition and subtraction of
fractions as joining and separating parts referring to the
same wholeb. 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, c. Add and subtract mixed
numbers with like denominators, e.g., by replacing each
mixed number with an equivalent fraction, and/or by
using properties of operations and the relationship
between addition and subtraction.
Unit Assessments
Administer Pre and Post Assessments for Unit 5 in the Third Grade Share Point Folder.
Grade 3 Unit 5 Reasoning about Fraction Comparison and Equivalence
March 2013