Standards for Mathematical Practice:
Standard 2: Reason abstractly and quantitatively
The Standard:
Mathematically proficient students make sense of quantities and their relationships in problem situations. They bring two
complementary abilities to bear on problems involving quantitative relationships: the ability to decontextualize—to abstract a given
situation and represent it symbolically and manipulate the representing symbols as if they have a life of their own, without necessarily
attending to their referents—and the ability to contextualize, to pause as needed during the manipulation process in order to probe into
the referents for the symbols involved. Quantitative reasoning entails habits of creating a coherent representation of the problem at
hand; considering the units involved; attending to the meaning of quantities, not just how to compute them; and knowing and flexibly
using different properties of operations and objects.
Classroom Observations:
Teachers who are developing students’ capacity to "reason abstractly and quantitatively" help their learners understand the
relationships between problem scenarios and mathematical representation, as well as how the symbols represent strategies for
solution. A middle childhood teacher might ask her students to reflect on what each number in a fraction represents as parts of a
whole. A different middle childhood teacher might ask his students to discuss different sample operational strategies for a patterning
problem, evaluating which is the most efficient and accurate means of finding a solution. Visit the video excerpts below to view these
teachers engaging their students in abstract and quantitative reasoning.
http://www.insidemathematics.org/index.php/mathematical-practice-standards to view multiple examples of teachers engaging students in
reasoning abstractly and quantitatively.
Students:




Represent a problem with symbols
Explain their thinking
Use numbers flexibly by applying properties of operations
and place value
Examine the reasonableness of their answers/calculations
Math Practice
Reason Abstractly and
Quantitatively
Because Teachers:
 Ask students to explain their thinking regardless of accuracy
 Highlight flexible use of numbers
 Facilitate discussion through guided questions and
representations
 Accept varied solutions/representations
Math Solutions
Key Points
 make sense of quantities and their relationships in
problem situations
 decontextualize - abstract and represent a problem
situation symbolically and manipulate those symbols
without attending to their referents
 contextualize - pause during problem solving to
Students might think or do:
 “How can I capture important information in a diagram
or model?”
 “What solution path does this diagram or model imply?”
 “OK, I’ve done all these calculations; now, what does that
mean in the problem? Does my answer make sense for
answering this problem?”
connect symbolic work back to the context of the problem  Given the problem: There are 3/5 as many boys as girls. If
 Pay attention to the important quantities and relationships
there are 45 boys, how many girls are there?, a student
between them
can create a diagram that shows the relationship between
 use representations to highlight those relationships and
the number.
the underlying mathematical structure of a problem
Education Development Center, Inc.
Reason Abstractly and Quantitatively
Questions to Develop Mathematical Thinking
 Make sense of quantities and their relationships.
 What do the numbers used in the problem represent?
 Are able to decontextualize (represent a situation symbolically
 What is the relationship of the quantities?
and manipulate the symbols) and contextualize (make
 How is ___ related to ___?
meaning of the symbols in a problem) quantitative
 What properties might we use to find a solution?
relationships.
 What does ___ mean to you? (e.g., symbol, quantity, diagram)
 Understand the meaning of quantities and are flexible in the
 How did you decide in this task that you needed to use . . . ?
use of operations and their properties.
 Could we have used another operation or property to solve this task?
 Create a logical representation of the problem.
Why or why not?
 Attends to the meaning of quantities, not just how to compute
them.
CCSS-M Flip Books: http://katm.org/wp/common-core/
Practice
Reason
Abstractly
and
Quantitativ
ely
Needs Improvement
Task:
 Lacks context.
 Does not make use of multiple
representations or solution
paths.
Teacher:
 Does not expect students to
interpret representations.
 Expects students to memorize
procedures with no connection
to meaning.
Emerging
(teacher does thinking)
Task:
 Is embedded in a contrived
context.
Teacher:
 Expects students to model and
interpret tasks using a single
representation.
 Explains connections between
procedures and meaning.
Proficient
(teacher mostly models)
Task:
 Has realistic context.
 Requires students to frame
solutions in a context.
 Has solutions that can be
expressed with multiple
representations.
Teacher:
 Expects students to interpret and
model using multiple
representations.
 Provides structure for students to
connect algebraic procedures to
contextual meaning.
 Links mathematical solution with
a question’s answer.
Exemplary
(students take ownership)
Task:
 Has relevant realistic
context.
Teacher:
 Expects students to
interpret, model, and
connect multiple
representations.
 Prompts students to
articulate connections
between algebraic
procedures and
contextual meaning.
Institute for Advanced Study
Park City Mathematics Institute