Grade 3 Mathematics, Quarter 2, Unit 2.1
Fractions as Parts of a Whole
Overview
Number of Instructional Days:
5
(1 day = 45–60 minutes)
Content to be Learned
Mathematical Practices to Be Integrated
•
Use appropriate tools strategically.
Partition shapes into parts with equal areas and
express each equal part as a unit fraction (1/b)
when the whole has b equal parts. (Each part is
1/3 when there are 3 equal parts.)
•
Understand a fraction a/b as the quantity
formed by a parts of size 1/b. (2/3 is two 1/3s)
•
Represent fractional parts by using the standard
fraction notation (1/2; 3/4)—limited to
fractions with denominators of 2, 3, 4, 6, and 8.
•
Use concrete models (number line, fraction
bars, fraction strips, fraction circles) to develop
conceptual understanding of fraction
quantities.
•
Choose appropriate models to demonstrate
understanding of fraction concepts.
Essential Questions
•
How do you identify and record the fraction of
a given shape?
•
What does the denominator tell you about a
fraction?
•
How do you partition this shape so the fraction
____ is represented?
•
How you can represent a unit fraction using a
variety of materials?
•
What does the numerator tell you about a
fraction?
•
If a shape is divided into ____(4) equal pieces,
what is the size of each piece? How many
pieces are needed to show ____ (3/4)?
Southern Rhode Island Regional Collaborative with process support from The Charles A. Dana Center at the University of Texas at Austin 17 Grade 8 Mathematics, Quarter 2, Unit 2.1
Fractions as Parts of a Whole (5 days)
Written Curriculum
Common Core State Standards for Mathematical Content
Geometry
3.G
Reason with shapes and their attributes.
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.
Number and Operations—Fractions5
5
3.NF
Grade 3 expectations in this domain are limited to fractions with denominators 2, 3, 4, 6, and 8.
Develop understanding of fractions as numbers.
3.NF.1
Understand a fraction 1/b as the quantity formed by 1 part when a whole is partitioned into b
equal parts; understand a fraction a/b as the quantity formed by a parts of size 1/b.
Common Core Standards for Mathematical Practice
5
Use appropriate tools strategically.
Mathematically proficient students consider the available tools when solving a mathematical problem.
These tools might include pencil and paper, concrete models, a ruler, a protractor, a calculator, a
spreadsheet, a computer algebra system, a statistical package, or dynamic geometry software. Proficient
students are sufficiently familiar with tools appropriate for their grade or course to make sound decisions
about when each of these tools might be helpful, recognizing both the insight to be gained and their
limitations. For example, mathematically proficient high school students analyze graphs of functions and
solutions generated using a graphing calculator. They detect possible errors by strategically using
estimation and other mathematical knowledge. When making mathematical models, they know that
technology can enable them to visualize the results of varying assumptions, explore consequences, and
compare predictions with data. Mathematically proficient students at various grade levels are able to
identify relevant external mathematical resources, such as digital content located on a website, and use
them to pose or solve problems. They are able to use technological tools to explore and deepen their
understanding of concepts.
Clarifying the Standards
Prior Learning
Students in grade 2 partitioned circles and rectangles into two, three, or four equal shares and identified
the numbers of halves, thirds, and fourths using pictures and words only. Standard fraction notation was
not introduced.
Southern Rhode Island Regional Collaborative with process support from The Charles A. Dana Center at the University of Texas at Austin 18 Grade 8 Mathematics, Quarter 2, Unit 2.1
Fractions as Parts of a Whole (5 days)
Current Learning
Developing an understanding of unit fractions as numbers is a critical area. In this unit, students partition
shapes into 2, 3, 4, 6, and 8 equal parts with equal areas and express each part as a unit fraction (1/b)
when the whole has b equal parts. They are now using the standard fraction notation (1/4; 1/2) and
developing the understanding that the size of a fractional part is relative to the size of the whole. They are
identifying a fraction a/b as the quantity formed by a parts of size 1/b. Students recognize that two 1/3s
are the same amount as 2/3. They understand and use the terms numerator and denominator.
In Units 2.2 and 3.1 they use their understanding of fractions of an area to develop and reinforce their
understanding of fractions as numbers on a number line. They develop an understanding of equivalence of
simple fractions and whole numbers as fractions. Students compare two fractions with the same
numerator or the same denominator by reasoning about their size.
Future Learning
In grade 4, students will further develop their understanding of fraction equivalence by comparing two
fractions with different numerators and different denominators. They will apply knowledge of composing
and decomposing fractions and operations on whole numbers to add and subtract fractions with like
denominators and multiply fractions by a whole number.
Additional Findings
According to the Progressions 3–5 Number and Operations—Fractions, “Grade 3 students start with unit
fractions (fractions with numerator 1), which are formed by partitioning a whole into equal parts and
taking one part, e.g., if a whole is partitioned into 4 equal parts then each part is 1/4 of the whole, and 4
copies of that part make the whole. Next, students build fractions from unit fractions, seeing the
numerator 3 of 3/4 as saying that 3/4 is the quantity you get by putting 3 of the 1/4s together. They read
any fraction this way, and in particular there is no need to introduce ‘proper fractions’ and ‘improper
fractions’ initially; 5/3 is the quantity you get by combining 5 parts together when the whole is divided
into 3 equal parts. Two important aspects of fractions provide opportunities for the mathematical practice
of attending to precision (MP6): Specifying the whole. Explaining what is meant by ‘equal parts’ (p. 2).
Southern Rhode Island Regional Collaborative with process support from The Charles A. Dana Center at the University of Texas at Austin 19 Grade 8 Mathematics, Quarter 2, Unit 2.1
Fractions as Parts of a Whole (5 days)
Southern Rhode Island Regional Collaborative with process support from The Charles A. Dana Center at the University of Texas at Austin 20 Grade 3 Mathematics, Quarter 2, Unit 2.2
Fractions as Numbers
Overview
Number of Instructional Days:
10
(1 day = 45–60 minutes)
Content to be Learned
Mathematical Practices to Be Integrated
•
Understand a fraction as a number on the
number line.
Use appropriate tools strategically.
•
Represent fractions on a number line diagram
in which they have defined the interval from
0–1 as the whole.
•
•
•
Consider available tools when solving a
mathematical problem (e.g., concrete models
such as fraction bars, fraction strips, fraction
circles, number line, ruler).
Express whole numbers as fractions.
•
Recognize fractions that are equivalent to
whole numbers (4/4; 6/1).
Makes sound decisions about when each tool
might be helpful.
•
Detect possible errors by strategically using
estimation and other mathematical knowledge.
•
Generate measurement data by using rulers
marked with halves and fourths of an inch.
•
Show the data on a line plot where the
horizontal scale is marked off in whole
numbers, halves, or quarters.
Essential Questions
•
How do you represent a whole number as a
fraction?
•
How do you represent your data on a labeled
line plot diagram?
•
How would you show equivalent fractions on a
number line diagram?
•
What steps must you take when deciding where
to place a fraction on a number line diagram?
•
How do you know if two fractions are
equivalent? How do you know if they are not
equivalent?
•
How long is this item to the nearest whole
number, 1/2 or 1/4 of an inch?
•
Where would the following fractions be located
on a number line diagram?
Southern Rhode Island Regional Collaborative with process support from The Charles A. Dana Center at the University of Texas at Austin 21 Grade 3 Mathematics, Quarter 2, Unit 2.2
Fractions as Numbers (10 days)
Written Curriculum
Common Core State Standards for Mathematical Content
Number and Operations—Fractions5
5
3.NF
Grade 3 expectations in this domain are limited to fractions with denominators 2, 3, 4, 6, and 8.
Develop understanding of fractions as numbers.
3.NF.2
Understand a fraction as a number on the number line; represent fractions on a number line
diagram.
a.
3.NF.3
Represent a fraction 1/b on a number line diagram by defining the interval from 0 to 1 as
the whole and partitioning it into b equal parts. Recognize that each part has size 1/b and
that the endpoint of the part based at 0 locates the number 1/b on the number line.
Explain equivalence of fractions in special cases, and compare fractions by reasoning about
their size.
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.
Measurement and Data
3.MD
Represent and interpret data.
3.MD.4
Generate measurement data by measuring lengths using rulers marked with halves and fourths
of an inch. Show the data by making a line plot, where the horizontal scale is marked off in
appropriate units—whole numbers, halves, or quarters.
Common Core Standards for Mathematical Practice
5
Use appropriate tools strategically.
Mathematically proficient students consider the available tools when solving a mathematical problem.
These tools might include pencil and paper, concrete models, a ruler, a protractor, a calculator, a
spreadsheet, a computer algebra system, a statistical package, or dynamic geometry software. Proficient
students are sufficiently familiar with tools appropriate for their grade or course to make sound decisions
about when each of these tools might be helpful, recognizing both the insight to be gained and their
limitations. For example, mathematically proficient high school students analyze graphs of functions and
solutions generated using a graphing calculator. They detect possible errors by strategically using
estimation and other mathematical knowledge. When making mathematical models, they know that
technology can enable them to visualize the results of varying assumptions, explore consequences, and
compare predictions with data. Mathematically proficient students at various grade levels are able to
identify relevant external mathematical resources, such as digital content located on a website, and use
them to pose or solve problems. They are able to use technological tools to explore and deepen their
understanding of concepts.
Southern Rhode Island Regional Collaborative with process support from The Charles A. Dana Center at the University of Texas at Austin 22 Grade 3 Mathematics, Quarter 2, Unit 2.2
Fractions as Numbers (10 days)
Clarifying the Standards
Prior Learning
Students in grade 2 partitioned circles and rectangles into two, three, or four equal shares and identified
the numbers of halves, thirds, and fourths using pictures and words only. Standard fraction notation was
not introduced. Second grade students have used appropriate tools such as rulers, yardsticks, meter sticks,
and measuring tapes to estimate and measure length. Students used units of inches, feet, centimeters, and
meters. Students represented measurement data on a line plot involving whole numbers.
Current Learning
In the previous unit, students develop an understanding of unit fractions. They partition shapes into 2, 3,
4, 6, and 8 equal parts with equal areas and expressed each as a unit fraction (1/b) when the whole has b
equal parts. They use the standard fraction notation (1/2, 3/4). Students identify a fraction a/b as the
quantity formed by a parts of size 1/b. (3/8 = 3 parts of 1/8 each). They use the terms numerator and
denominator.
In Unit 2.1, students develop an understanding of fractions within an area model. In this unit, they extend
their understanding of fractions as a distance on a number line. The context of linear measurement
supports this development. Students generate measurement data by measuring lengths using rulers
marked with halves and fourths of an inch. They show the data by making a line plot, where the
horizontal scale is marked off in appropriate units—whole numbers, halves, or quarters.
In this unit, students continue to develop their understanding of a fraction as a number by using the
number line model to explore unit fractions. This is a critical area of focus for students this year. They
understand the fraction represents the distance from 0 on a number line. They define the interval from 0 to
1 as the whole and partition it into b equal parts while recognizing that each part has size 1/b. (For
example, 2/3 is ‘two’ intervals of ‘1/3’ from zero.) Students explore whole numbers and their fractional
equivalence. (They see 2 as 2/1 or 4/2 or 6/3 and 1 as 2/2 or 3/3.)
Best practice indicates referring to fractional quantities as an amount or a distance from zero, not as a part
of a set or “three out of four” for 3/4.
Later in grade 3, students use their understanding of fractions on a number line to compare fractions by
reasoning about their size. They generate simple equivalent fractions (1/2 = 2/4; 2/3 = 4/6).
Future Learning
In grade 4, students will further develop their understanding of fraction equivalence and use their
understanding of how to compose fractions from unit fractions and decompose fractions into unit
fractions. They will solve problems involving addition and subtraction of fractions with like denominators
and multiply fractions by a whole number.
Southern Rhode Island Regional Collaborative with process support from The Charles A. Dana Center at the University of Texas at Austin 23 Grade 3 Mathematics, Quarter 2, Unit 2.2
Fractions as Numbers (10 days)
Additional Findings
According to Progressions 3–5 Number and Operations—Fractions, “As students move towards thinking
of fractions as points on the number line, they develop an understanding of order in terms of position.
Given two fractions—thus two points on the number line—the one to the left is said to be smaller and the
one to right is said to be larger. This understanding of order as position will become important in Grade 6
when students start working with negative numbers.” (p. 4)
According to PARCC Model Content Frameworks Mathematics Grades 3–11, “Students in grade 3 begin
to enlarge their concept of numbers by developing an understanding of fractions as numbers. This work
will continue in grades 3–6, preparing the way for work with the complete rational number system in
grades 6–7.” (p. 15)
“It is critical that students at this grade are able to place fractions on a number line diagram and
understand them as a related component of their ever expanding number system.” (p. 16)
Southern Rhode Island Regional Collaborative with process support from The Charles A. Dana Center at the University of Texas at Austin 24 Grade 3 Mathematics, Quarter 2, Unit 2.3
Multiplication and Division Within 100
Overview
Number of Instructional Days:
10
(1 day = 45–60 minutes)
Content to be Learned
Mathematical Practices to Be Integrated
•
Multiply and divide within 100.
•
Develop and use strategies based on the
relationship between multiplication and
division and the commutative and distributive
properties of multiplication to solve problems.
Construct viable arguments and critique the
reasoning of others.
•
Solve one-step word problems using the four
operations.
•
Represent problems using equations.
•
Apply strategies of rounding and mental
computation to check for reasonableness.
•
Justify conclusions and explain thinking by
communicating them to others.
•
Compare strategies for effectiveness.
•
Support arguments using object, pictures,
and/or drawings.
Attend to precision.
•
Use the equal sign appropriately.
•
Develop efficient strategies and calculate
accurately.
•
Check their work.
Look for and make use of structure.
•
Look for patterns in multiplication and
division.
Essential Questions
•
How can multiplication help you solve division
problems?
•
How can simpler multiplication facts help you
solve a more difficult fact?
•
What strategies can be used to find products
and/or quotients?
•
How do you know that your equation
accurately represents this word problem?
•
How can you use the array model to help you
solve multiplication problems?
•
How do you know your answer is reasonable?
•
What number sentences could be used to solve
this problem?
Southern Rhode Island Regional Collaborative with process support from The Charles A. Dana Center at the University of Texas at Austin 25 Grade 3 Mathematics, Quarter 2, Unit 2.3
Multiplication and Division Within 100 (10 days)
Written Curriculum
Common Core State Standards for Mathematical Content
Operations and Algebraic Thinking
3.OA
Multiply and divide within 100.
3.OA.7
Fluently multiply and divide within 100, using strategies such as the relationship between
multiplication and division (e.g., knowing that 8 × 5 = 40, one knows 40 ÷ 5 = 8) or properties
of operations. By the end of Grade 3, know from memory all products of two one-digit
numbers.
Understand properties of multiplication and the relationship between multiplication and division.
3.OA.5
Apply properties of operations as strategies to multiply and divide.2 Examples: If 6 × 4 = 24 is
known, then 4 × 6 = 24 is also known. (Commutative property of multiplication.) 3 × 5 × 2
can be found by 3 × 5 = 15, then 15 × 2 = 30, or by 5 × 2 = 10, then 3 × 10 = 30.
(Associative property of multiplication.) Knowing that 8 × 5 = 40 and 8 × 2 = 16, one can
find 8 × 7 as 8 × (5 + 2) = (8 × 5) + (8 × 2) = 40 + 16 = 56. (Distributive property.)
2
Students need not use formal terms for these properties.
Solve problems involving the four operations, and identify and explain patterns in arithmetic.
3.OA.8
Solve two-step word problems using the four operations. Represent these problems using
equations with a letter standing for the unknown quantity. Assess the reasonableness of
answers using mental computation and estimation strategies including rounding.3
3
This standard is limited to problems posed with whole numbers and having whole-number answers; students
should know how to perform operations in the conventional order when there are no parentheses to specify a
particular order (Order of Operations).
Common Core Standards for Mathematical Practice
3
Construct viable arguments and critique the reasoning of others.
Mathematically proficient students understand and use stated assumptions, definitions, and previously
established results in constructing arguments. They make conjectures and build a logical progression of
statements to explore the truth of their conjectures. They are able to analyze situations by breaking them
into cases, and can recognize and use counterexamples. They justify their conclusions, communicate them
to others, and respond to the arguments of others. They reason inductively about data, making plausible
arguments that take into account the context from which the data arose. Mathematically proficient
students are also able to compare the effectiveness of two plausible arguments, distinguish correct logic or
reasoning from that which is flawed, and—if there is a flaw in an argument—explain what it is.
Elementary students can construct arguments using concrete referents such as objects, drawings,
diagrams, and actions. Such arguments can make sense and be correct, even though they are not
generalized or made formal until later grades. Later, students learn to determine domains to which an
argument applies. Students at all grades can listen or read the arguments of others, decide whether they
make sense, and ask useful questions to clarify or improve the arguments.
Southern Rhode Island Regional Collaborative with process support from The Charles A. Dana Center at the University of Texas at Austin 26 Grade 3 Mathematics, Quarter 2, Unit 2.3
6
Multiplication and Division Within 100 (10 days)
Attend to precision.
Mathematically proficient students try to communicate precisely to others. They try to use clear
definitions in discussion with others and in their own reasoning. They state the meaning of the symbols
they choose, including using the equal sign consistently and appropriately. They are careful about
specifying units of measure, and labeling axes to clarify the correspondence with quantities in a problem.
They calculate accurately and efficiently, express numerical answers with a degree of precision
appropriate for the problem context. In the elementary grades, students give carefully formulated
explanations to each other. By the time they reach high school they have learned to examine claims and
make explicit use of definitions.
7
Look for and make use of structure.
Mathematically proficient students look closely to discern a pattern or structure. Young students, for
example, might notice that three and seven more is the same amount as seven and three more, or they may
sort a collection of shapes according to how many sides the shapes have. Later, students will see 7 × 8
equals the well remembered 7 × 5 + 7 × 3, in preparation for learning about the distributive property. In
the expression x2 + 9x + 14, older students can see the 14 as 2 × 7 and the 9 as 2 + 7. They recognize the
significance of an existing line in a geometric figure and can use the strategy of drawing an auxiliary line
for solving problems. They also can step back for an overview and shift perspective. They can see
complicated things, such as some algebraic expressions, as single objects or as being composed of several
objects. For example, they can see 5 – 3(x – y)2 as 5 minus a positive number times a square and use that
to realize that its value cannot be more than 5 for any real numbers x and y.
Clarifying the Standards
Prior Learning
In grade 2, students used additive thinking to skip count by 5s, 10s, and 100s, and used additive thinking
to find the total number of objects arranged in arrays up to 5 row and 5 columns.
Current Learning
In this unit, students continue to develop their conceptual understanding of multiplication. In unit 1.3,
they use area as a context for developing multiplicative thinking and to interpret products of whole
numbers as the total number of objects grouped equally. In Unit 1.4, they study patterns and relationships
in multiplication facts and the commutative strategy of multiplication to begin multiplying within 100.
Students build on previous learned strategies to multiply and divide within 100 and solve single-step word
problems of various types (see CCSS table 1, pp. 88, 89) with whole numbers using all four operations.
They develop an understanding of the relationship between multiplication and division as they apply the
commutative property.
Throughout third grade, students continue to develop their understanding of multiplication and division.
In Unit 3.3, they develop more strategies for multiplying and dividing within 100 and solve two-step
problems with a letter standing for the unknown quantity. In Unit 4.4, students solve two-step problems
using all four operations and represent these problems using equations with a letter standing for the
unknown quantity. By the end of grade 3, they will know from memory all products of two one-digit
numbers.
Southern Rhode Island Regional Collaborative with process support from The Charles A. Dana Center at the University of Texas at Austin 27 Grade 3 Mathematics, Quarter 2, Unit 2.3
Multiplication and Division Within 100 (10 days)
Future Learning
In grade 4, they will solve multi-step word problems including those in which remainders must be
interpreted. They will multiply up to 4-digit by 1-digit whole numbers and two 2-digit numbers and find
whole number quotients and remainders with up to 4-digit dividends and 1-digit divisors.
Additional Findings
According to the PARCC Model Content Frameworks Mathematics Grades 3–11, “Students must begin
multiplication and division at or near the very start of the year in order to allow time for understanding
and fluency to develop” (p. 15)
According to the Progressions Counting and Cardinality, K–5, Operations and Algebraic Thinking,
“Note that mastering this material, and reaching fluency in single- digit multiplications and related
divisions with understanding, 3.OA.7 may be quite time consuming because there are no general
strategies for multiplying or dividing all single-digit numbers as there are for addition and subtraction.
Instead, there are many patterns and strategies dependent upon specific numbers. So it’s imperative that
extra time and support be provided if needed.” (p. 22)
Southern Rhode Island Regional Collaborative with process support from The Charles A. Dana Center at the University of Texas at Austin 28 Grade 3 Mathematics, Quarter 2, Unit 2.4
Application of Area Concepts
Overview
Number of Instructional Days:
15
(1 day = 45–60 minutes)
Content to be Learned
Mathematical Practices to Be Integrated
•
Find areas of rectangles by tiling.
•
Relate finding area to multiplication.
Make sense of problems and persevere in solving
them.
•
Find perimeter of polygons by determining the
length of an unknown side.
•
Use concrete objects to conceptualize area and
perimeter.
•
Recognize attributes that quadrilaterals share.
•
Justify and communicate solutions using
pictures, words, numbers, etc.
Look for and express regularity in repeated
reasoning.
•
Notice repetitive actions in computation and
look for efficient methods.
Model with mathematics.
•
Represent problems in multiple ways.
•
Connect different representations and explain
these representations.
•
What attributes do all quadrilaterals share?
•
Given the perimeter and the length of one side
of a rectangle, how can you determine the
length of the other side?
Essential Questions
•
Do rectangles with the same area always have
the same perimeter?
•
Do rectangle with the same perimeter always
have the same area?
•
How would you explain the process for finding
the area of a rectangle?
Southern Rhode Island Regional Collaborative with process support from The Charles A. Dana Center at the University of Texas at Austin 29 Grade 3 Mathematics, Quarter 2, Unit 2.4
Application of Area Concepts (15 days)
Written Curriculum
Common Core State Standards for Mathematical Content
Measurement and Data
3.MD
Geometric measurement: understand concepts of area and relate area to multiplication and to
addition.
3.MD.7
Relate area to the operations of multiplication and addition.
a.
Find the area of a rectangle with whole-number side lengths by tiling it, and show that the
area is the same as would be found by multiplying the side lengths.
b.
Multiply side lengths to find areas of rectangles with whole-number side lengths in the
context of solving real world and mathematical problems, and represent whole-number
products as rectangular areas in mathematical reasoning.
Geometric measurement: recognize perimeter as an attribute of plane figures and distinguish
between linear and area measures.
3.MD.8
Solve real world and mathematical problems involving perimeters of polygons, including
finding the perimeter given the side lengths, finding an unknown side length, and exhibiting
rectangles with the same perimeter and different areas or with the same area and different
perimeters.
Geometry
3.G
Reason with shapes and their attributes.
3.G.1
Understand that shapes in different categories (e.g., rhombuses, rectangles, and others) may
share attributes (e.g., having four sides), and that the shared attributes can define a larger
category (e.g., quadrilaterals). Recognize rhombuses, rectangles, and squares as examples of
quadrilaterals, and draw examples of quadrilaterals that do not belong to any of these
subcategories.
Common Core Standards for Mathematical Practice
1
Make sense of problems and persevere in solving them.
Mathematically proficient students start by explaining to themselves the meaning of a problem and
looking for entry points to its solution. They analyze givens, constraints, relationships, and goals. They
make conjectures about the form and meaning of the solution and plan a solution pathway rather than
simply jumping into a solution attempt. They consider analogous problems, and try special cases and
simpler forms of the original problem in order to gain insight into its solution. They monitor and evaluate
their progress and change course if necessary. Older students might, depending on the context of the
problem, transform algebraic expressions or change the viewing window on their graphing calculator to
get the information they need. Mathematically proficient students can explain correspondences between
equations, verbal descriptions, tables, and graphs or draw diagrams of important features and
relationships, graph data, and search for regularity or trends. Younger students might rely on using
Southern Rhode Island Regional Collaborative with process support from The Charles A. Dana Center at the University of Texas at Austin 30 Grade 3 Mathematics, Quarter 2, Unit 2.4
Application of Area Concepts (15 days)
concrete objects or pictures to help conceptualize and solve a problem. Mathematically proficient students
check their answers to problems using a different method, and they continually ask themselves, “Does
this make sense?” They can understand the approaches of others to solving complex problems and
identify correspondences between different approaches.
4
Model with mathematics.
Mathematically proficient students can apply the mathematics they know to solve problems arising in
everyday life, society, and the workplace. In early grades, this might be as simple as writing an addition
equation to describe a situation. In middle grades, a student might apply proportional reasoning to plan a
school event or analyze a problem in the community. By high school, a student might use geometry to
solve a design problem or use a function to describe how one quantity of interest depends on another.
Mathematically proficient students who can apply what they know are comfortable making assumptions
and approximations to simplify a complicated situation, realizing that these may need revision later. They
are able to identify important quantities in a practical situation and map their relationships using such
tools as diagrams, two-way tables, graphs, flowcharts and formulas. They can analyze those relationships
mathematically to draw conclusions. They routinely interpret their mathematical results in the context of
the situation and reflect on whether the results make sense, possibly improving the model if it has not
served its purpose.
8
Look for and express regularity in repeated reasoning.
Mathematically proficient students notice if calculations are repeated, and look both for general methods
and for shortcuts. Upper elementary students might notice when dividing 25 by 11 that they are repeating
the same calculations over and over again, and conclude they have a repeating decimal. By paying attention
to the calculation of slope as they repeatedly check whether points are on the line through (1, 2) with slope
3, middle school students might abstract the equation (y – 2)/(x – 1) = 3. Noticing the regularity in the way
terms cancel when expanding (x – 1)(x + 1), (x – 1)(x2 + x + 1), and (x – 1)(x3 + x2 + x + 1) might lead them
to the general formula for the sum of a geometric series. As they work to solve a problem, mathematically
proficient students maintain oversight of the process, while attending to the details. They continually
evaluate the reasonableness of their intermediate results.
Clarifying the Standards
Prior Learning
In grade 2, students described and analyzed shapes by examining their sides and angles. They developed
the foundation for understanding area. They recognized and drew shapes having specified attributes.
Current Learning
In this unit, students build on their understanding of perimeter developed in Unit 1.2. In this unit, students
continue to develop an understanding of the concept of perimeter by using real-world and classroom
contexts (i.e., walking around the perimeter of a room; using elastics on a geo-board). They use addition
to find perimeter and recognize the patterns that exist when finding the sum of the length and width of
rectangles. Given the perimeter and a length or width, students use objects or pictures to find the missing
length or width.
Students in grade 3 tile areas of rectangles with whole number sides, determine the area, record the length
and width of the rectangle, investigate the pattern in the numbers and discover that the area is length times
width.
Southern Rhode Island Regional Collaborative with process support from The Charles A. Dana Center at the University of Texas at Austin 31 Grade 3 Mathematics, Quarter 2, Unit 2.4
Application of Area Concepts (15 days)
Students recognize shapes that are and are not quadrilaterals by examining the properties of the geometric
figures.
Later this year in Unit 3.2, students find the area of rectilinear figures (polygons having all right angles)
by decomposing them into nonoverlapping rectangles and adding the areas of the nonoverlapping parts.
They will use concrete area models to reinforce their understanding of the distributive property of
multiplication. They will apply their understanding of area and perimeter to explore relationships between
area and perimeter.
Future Learning
In grade 4, they will apply the area and perimeter formulas for rectangles in real-world and mathematical
problems and will classify 2-D figures based on attribute of their lines and angles.
Additional Findings
According to the PARCC Model Content Frameworks, “Area is a major concept within measurement, and
area models must function as a support for multiplicative reasoning in grade 3 and beyond” (p. 60).
Southern Rhode Island Regional Collaborative with process support from The Charles A. Dana Center at the University of Texas at Austin 32