Grade 1 Common Core Standards for
Mathematics
The Common Core State Standards provide
a consistent, clear understanding of what students are expected
to learn, so teachers and parents know what they need to do to
help them. The standards are designed to be robust and relevant
to the real world, reflecting the knowledge and skills that our
young people need for success in college and careers. With
American students fully prepared for the future, our communities
will be best positioned to compete successfully in the global
economy. 
In Grade 1, instructional time should focus on four critical areas: (1)
developing understanding of addition, subtraction, and strategies for
addition and subtraction within 20; (2) developing understanding of
whole number relationships and place value, including grouping in tens
and ones; (3) developing understanding of linear measurement and
measuring lengths as iterating length units; and (4) reasoning about
attributes of, and composing and decomposing geometric shapes.

1. Students develop strategies for adding and subtracting whole
numbers based on their prior work with small numbers. They use a
variety of models, including discrete objects and lengthbased
models (e.g., cubes connected to form lengths), to model addto,
takefrom, puttogether, takeapart, and compare situations to
develop meaning for the operations of addition and subtraction, and
to develop strategies to solve arithmetic problems with these
operations. Students understand connections between counting and
addition and subtraction (e.g., adding two is the same as counting
on two). They use properties of addition to add whole numbers and to
create and use increasingly sophisticated strategies based on these
properties (e.g., “making tens”) to solve addition and subtraction
problems within 20. By comparing a variety of solution strategies,
children build their understanding of the relationship between
addition and subtraction.

2. Students develop, discuss, and use efficient, accurate, and
generalizable methods to add within 100 and subtract multiples of
10. They compare whole numbers (at least to 100) to develop
understanding of and solve problems involving their relative sizes.
They think of whole numbers between 10 and 100 in terms of tens and
ones (especially recognizing the numbers 11 to 19 as composed of a
ten and some ones). Through activities that build number sense, they
understand the order of the counting numbers and their relative
magnitudes.

3. Students develop an understanding of the meaning and processes of
measurement, including underlying concepts such as iterating (the
mental activity of building up the length of an object with
equalsized units) and the transitivity principle for indirect
measurement.^{1}

4. Students compose and decompose plane or solid figures (e.g., put
two triangles together to make a quadrilateral) and build
understanding of partwhole relationships as well as the properties
of the original and composite shapes. As they combine shapes, they
recognize them from different perspectives and orientations,
describe their geometric attributes, and determine how they are
alike and different, to develop the background for measurement and
for initial understandings of properties such as congruence and
symmetry.
Grade 1 Overview

Operations and Algebraic Thinking

Represent and solve problems involving addition and subtraction.

Understand and apply properties of operations and the
relationship between addition and subtraction.

Add and subtract within 20.

Work with addition and subtraction equations.

Number and Operations in Base Ten

Extend the counting sequence.

Understand place value.

Use place value understanding and properties of operations to
add and subtract.

Measurement and Data

Measure lengths indirectly and by iterating length units.

Tell and write time.

Represent and interpret data.

Geometry

Reason with shapes and their attributes.

Mathematical Practices

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.