
Legend:  Knowledge and Skills Statements (TEKS) identified by TEA are in italicized, bolded, black text.
 Student Expectations (TEKS) identified by TEA are in bolded, black text.
 Portions of the Student Expectations (TEKS) that are not included in this unit but are taught in previous or future units are indicated by a
strikethrough.

Legend:  Supporting information / clarifications (specificity) written by TEKS Resource System are in blue text.
 Unitspecific clarifications are in italicized, blue text.
 Information from Texas Education Agency (TEA), Texas College and Career Readiness Standards (TxCCRS), Texas Response to Curriculum Focal Points (TxRCFP) is labeled.
 A Partial Specificity label indicates that a portion of the specificity not aligned to this unit has been removed.

1.1 
Mathematical process standards. The student uses mathematical processes to acquire and demonstrate mathematical understanding. The student is expected to:


1.1A 
Apply mathematics to problems arising in everyday life, society, and the workplace.

Apply
MATHEMATICS TO PROBLEMS ARISING IN EVERYDAY LIFE, SOCIETY, AND THE WORKPLACE
Including, but not limited to:
 Mathematical problem situations within and between disciplines
 Everyday life
 Society
 Workplace
Note(s):
 The mathematical process standards may be applied to all content standards as appropriate.
 TxRCFP:
 Developing an understanding of place value
 Solving problems involving addition and subtraction
 Analyzing attributes of twodimensional shapes and threedimensional solids
 Developing the understanding of length
 TxCCRS:

1.1B 
Use a problemsolving model that incorporates analyzing given information, formulating a plan or strategy, determining a solution, justifying the solution, and evaluating the problemsolving process and the reasonableness of the solution.

Use
A PROBLEMSOLVING MODEL THAT INCORPORATES ANALYZING GIVEN INFORMATION, FORMULATING A PLAN OR STRATEGY, DETERMINING A SOLUTION, JUSTIFYING THE SOLUTION, AND EVALUATING THE PROBLEMSOLVING PROCESS AND THE REASONABLENESS OF THE SOLUTION
Including, but not limited to:
 Problemsolving model
 Analyze given information
 Formulate a plan or strategy
 Determine a solution
 Justify the solution
 Evaluate the problemsolving process and the reasonableness of the solution
Note(s):
 The mathematical process standards may be applied to all content standards as appropriate.
 TxRCFP:
 Developing an understanding of place value
 Solving problems involving addition and subtraction
 Analyzing attributes of twodimensional shapes and threedimensional solids
 Developing the understanding of length
 TxCCRS:
 VIII. Problem Solving and Reasoning

1.1C 
Select tools, including real objects, manipulatives, paper and pencil, and technology as appropriate, and techniques, including mental math, estimation, and number sense as appropriate, to solve problems.

Select
TOOLS, INCLUDING REAL OBJECTS, MANIPULATIVES, PAPER AND PENCIL, AND TECHNOLOGY AS APPROPRIATE, AND TECHNIQUES, INCLUDING MENTAL MATH, ESTIMATION, AND NUMBER SENSE AS APPROPRIATE, TO SOLVE PROBLEMS
Including, but not limited to:
 Appropriate selection of tool(s) and techniques to apply in order to solve problems
 Tools
 Real objects
 Manipulatives
 Paper and pencil
 Technology
 Techniques
 Mental math
 Estimation
 Number sense
Note(s):
 The mathematical process standards may be applied to all content standards as appropriate.
 TxRCFP:
 Developing an understanding of place value
 Solving problems involving addition and subtraction
 Analyzing attributes of twodimensional shapes and threedimensional solids
 Developing the understanding of length
 TxCCRS:
 VIII. Problem Solving and Reasoning

1.1D 
Communicate mathematical ideas, reasoning, and their implications using multiple representations, including symbols, diagrams, graphs, and language as appropriate.

Communicate
MATHEMATICAL IDEAS, REASONING, AND THEIR IMPLICATIONS USING MULTIPLE REPRESENTATIONS, INCLUDING SYMBOLS, DIAGRAMS, AND LANGUAGE AS APPROPRIATE
Including, but not limited to:
 Mathematical ideas, reasoning, and their implications
 Multiple representations, as appropriate
 Symbols
 Diagrams
 Language
Note(s):
 The mathematical process standards may be applied to all content standards as appropriate.
 TxRCFP:
 Developing an understanding of place value
 Solving problems involving addition and subtraction
 Analyzing attributes of twodimensional shapes and threedimensional solids
 Developing the understanding of length
 TxCCRS:
 IX. Communication and Representation

1.1E 
Create and use representations to organize, record, and communicate mathematical ideas.

Create, Use
REPRESENTATIONS TO ORGANIZE, RECORD, AND COMMUNICATE MATHEMATICAL IDEAS
Including, but not limited to:
 Representations of mathematical ideas
 Organize
 Record
 Communicate
 Evaluation of the effectiveness of representations to ensure clarity of mathematical ideas being communicated
 Appropriate mathematical vocabulary and phrasing when communicating mathematical ideas
Note(s):
 The mathematical process standards may be applied to all content standards as appropriate.
 TxRCFP:
 Developing an understanding of place value
 Solving problems involving addition and subtraction
 Analyzing attributes of twodimensional shapes and threedimensional solids
 Developing the understanding of length
 TxCCRS:
 IX. Communication and Representation

1.1F 
Analyze mathematical relationships to connect and communicate mathematical ideas.

Analyze
MATHEMATICAL RELATIONSHIPS TO CONNECT AND COMMUNICATE MATHEMATICAL IDEAS
Including, but not limited to:
 Mathematical relationships
 Connect and communicate mathematical ideas
 Conjectures and generalizations from sets of examples and nonexamples, patterns, etc.
 Current knowledge to new learning
Note(s):
 The mathematical process standards may be applied to all content standards as appropriate.
 TxRCFP:
 Developing an understanding of place value
 Solving problems involving addition and subtraction
 Analyzing attributes of twodimensional shapes and threedimensional solids
 Developing the understanding of length
 TxCCRS:

1.1G 
Display, explain, and justify mathematical ideas and arguments using precise mathematical language in written or oral communication.

Display, Explain, Justify
MATHEMATICAL IDEAS AND ARGUMENTS USING PRECISE MATHEMATICAL LANGUAGE IN WRITTEN OR ORAL COMMUNICATION
Including, but not limited to:
 Mathematical ideas and arguments
 Validation of conclusions
 Displays to make work visible to others
 Diagrams, visual aids, written work, etc.
 Explanations and justifications
 Precise mathematical language in written or oral communication
Note(s):
 The mathematical process standards may be applied to all content standards as appropriate.
 TxRCFP:
 Developing an understanding of place value
 Solving problems involving addition and subtraction
 Analyzing attributes of twodimensional shapes and threedimensional solids
 Developing the understanding of length
 TxCCRS:
 IX. Communication and Representation

1.3 
Number and operations. The student applies mathematical process standards to develop and use strategies for whole number addition and subtraction computations in order to solve problems. The student is expected to:


1.3B 
Use objects and pictorial models to solve word problems involving joining, separating, and comparing sets within 20 and unknowns as any one of the terms in the problem such as 2 + 4 = [ ]; 3 + [ ] = 7; and 5 = [ ] – 3.

Use
OBJECTS AND PICTORIAL MODELS TO SOLVE WORD PROBLEMS INVOLVING JOINING, SEPARATING, AND COMPARING SETS WITHIN 20 AND UNKNOWNS AS ANY ONE OF THE TERMS IN THE PROBLEM
Including, but not limited to:
 Whole numbers
 Counting (natural) numbers – the set of positive numbers that begins at one and increases by increments of one each time {1, 2, 3, ..., n}
 Whole numbers – the set of counting (natural) numbers and zero {0, 1, 2, 3, ..., n}
 Addition
 Sum – the total when two or more addends are joined
 Addend – a number being added or joined together with another number(s)
 Addition of whole numbers within 20
 Subtraction
 Difference – the remaining amount after the subtrahend has been subtracted from the minuend
 Minuend – a number from which another number will be subtracted
 Subtrahend – a number to be subtracted from a minuend
 Subtraction of whole numbers within 20
 Solutions recorded with a number sentence
 Number sentence – a mathematical statement composed of numbers, and/or an unknown(s), and/or an operator(s), and an equality or inequality symbol
 Number sentences, or equations, with equal sign at beginning or end
 Unknown in any position
 Concrete models
 Sets of objects within 20
 Base10 blocks, linking cubes, counters, etc.
 Pictorial models
 Base10 pictorials, number lines, strip diagrams, etc.
 Strip diagram – a linear model used to illustrate number relationships
 Mathematical and realworld problem situations
 Problems involving action
 Joining action result unknown
 Joining action change unknown
 Joining action start unknown
 Separating action result unknown
 Separating action change unknown
 Separating action start unknown
 Problems with no action
 Partpartwhole whole unknown
 Partpartwhole part unknown
 Additive comparison difference unknown
 Additive comparison compare quantity (larger quantity) unknown
 Additive comparison referent (smaller quantity) unknown
 Recognition of addition and subtraction as inverse operations
 Addition can be reversed by subtraction.
 Subtraction can be reversed by addition.
 Fact families – related number sentences using the same set of numbers
Note(s):
 Grade Level(s):
 Kindergarten modeled the action of joining to represent addition and the action of separating to represent subtraction in problems with the result unknown.
 Grade 1 introduces comparison problems.
 Various mathematical process standards will be applied to this student expectation as appropriate.
 TxRCFP:
 Solving problems involving addition and subtraction
 TxCCRS:
 I. Numeric Reasoning
 II.D. Algebraic Reasoning – Representations
 VIII. Problem Solving and Reasoning
 IX. Communication and Representation
 X. Connections

1.3D 
Apply basic fact strategies to add and subtract within 20, including making 10 and decomposing a number leading to a 10.

Apply
BASIC FACT STRATEGIES TO ADD AND SUBTRACT WITHIN 20, INCLUDING MAKING 10 AND DECOMPOSING A NUMBER LEADING TO A 10
Including, but not limited to:
 Whole numbers
 Counting (natural) numbers – the set of positive numbers that begins at one and increases by increments of one each time {1, 2, 3, ..., n}
 Whole numbers – the set of counting (natural) numbers and zero {0, 1, 2, 3, ..., n}
 Addition
 Sum – the total when two or more addends are joined
 Addend – a number being added or joined together with another number(s)
 Addition of whole numbers within 20
 Subtraction
 Difference – the remaining amount after the subtrahend has been subtracted from the minuend
 Minuend – a number from which another number will be subtracted
 Subtrahend – a number to be subtracted from a minuend
 Subtraction of whole numbers within 20
 Solutions recorded with a number sentence
 Number sentence – a mathematical statement composed of numbers, and/or an unknown(s), and/or an operator(s), and an equality or inequality symbol
 Number sentences, or equations, with equal sign at beginning or end
 Decompose numbers – to break a number into parts or smaller values
 Compose numbers – to combine parts or smaller values to form a number
 Basic fact strategies for addition
 Counting all
 Count the amount of the first addend and count on the amount of the other addend.
 Counting on
 Begin with the first addend and count on the amount of the other addend.
 Begin with the largest addend and count on the amount of the other addend.
 Plus 1
 Adding 1 related to sequential counting
 Plus 2
 Adding 2 related to skip counting
 Plus 0 (additive identity)
 Adding zero to a number does not affect the total.
 Making 10
 Composing two addends to form a sum of 10
 Hidden tens
 Decomposing a number leading to a 10
 Plus 10
 Add 1 ten in the tens place and add 0 in the ones place.
 Doubles
 Adding two of the same addend
 Double plus/minus 1
 Consecutive addends
 Double the smaller addend and add 1, or double the larger addend and subtract 1.
 Hidden doubles
 Decompose an addend to form a doubles fact.
 Inbetweens
 Addends that have exactly one number between them consecutively.
 Double the number between the addends.
 Fact families – related number sentences using the same set of numbers
 Recognition of addition and subtraction as inverse operations
 Commutative property
 Sum does not change when the order of the addends are switched.
 Plus 9
 Adding 9 is equivalent to adding 10 and subtracting 1.
 Basic fact strategies for subtraction
 Counting back
 Begin with the minuend and count back the amount of the subtrahend.
 Counting up
 Begin with the subtrahend and count up to the minuend.
 Minus 1
 Subtracting 1 related to sequentially counting backward once
 Minus 2
 Subtracting 2 related to sequentially counting backward twice
 Minus 0 (additive identity)
 Subtracting 0 from a number does not affect the total.
 Fact families – related number sentences using the same set of numbers
 Recognition of addition and subtraction as inverse operations
 Decompose the subtrahend
 Decompose the subtrahend to form a known fact.
 Decompose the minuend
 Decompose the minuend to form a known fact.
 Minus 9
 Subtracting 9 is equivalent to subtracting 10 and adding 1.
Note(s):
 Grade Level(s):
 Grade 1 introduces applying basic fact strategies to add and subtract within 20.
 Grade 2 will recall basic facts to add and subtract within 20 with automaticity.
 Various mathematical process standards will be applied to this student expectation as appropriate.
 TxRCFP:
 Solving problems involving addition and subtraction
 TxCCRS:
 I. Numeric Reasoning
 IX. Communication and Representation

1.3E 
Explain strategies used to solve addition and subtraction problems up to 20 using spoken words, objects, pictorial models, and number sentences.

Explain
STRATEGIES USED TO SOLVE ADDITION AND SUBTRACTION PROBLEMS UP TO 20 USING SPOKEN WORDS, OBJECTS, PICTORIAL MODELS, AND NUMBER SENTENCES
Including, but not limited to:
 Whole numbers
 Counting (natural) numbers – the set of positive numbers that begins at one and increases by increments of one each time {1, 2, 3, ..., n}
 Whole numbers – the set of counting (natural) numbers and zero {0, 1, 2, 3, ..., n}
 Mathematical and realworld problem situations
 Addition
 Sum – the total when two or more addends are joined
 Addend – a number being added or joined together with another number(s)
 Addition of whole numbers within 20
 Subtraction
 Difference – the remaining amount after the subtrahend has been subtracted from the minuend
 Minuend – a number from which another number will be subtracted
 Subtrahend – a number to be subtracted from a minuend
 Subtraction of whole numbers within 20
 Detailed explanation of solution process and strategy
 Addition strategies
 Counting all
 Counting on
 Plus 1
 Plus 2
 Plus 0 (additive identity)
 Making 10
 Hidden tens
 Plus 10
 Doubles
 Doubles plus/minus 1
 Hidden doubles
 Inbetweens
 Fact families
 Commutative property
 Plus 9
 Subtraction strategies
 Counting back
 Counting up
 Minus 1
 Minus 2
 Minus 0 (additive identity)
 Fact families
 Decompose the subtrahend
 Decompose the minuend
 Minus 9
 Connection between information in the problem and problem type
 Joining action situations
 Result unknown
 Change unknown
 Start unknown
 Separating action situations
 Result unknown
 Change unknown
 Start unknown
 Partpartwhole situations
 Whole unknown
 Part unknown
 Additive comparison situations
 Difference unknown
 Compare quantity (larger quantity) unknown
 Referent (smaller quantity) unknown
 Relationship between quantities of objects used, pictures drawn, and number sentences to the problem situation
 Explanation using spoken words
 Appropriate mathematical language for addition and subtraction situations
 Labels for quantities represented
 Explanation using objects
 Base10 blocks, linking cubes, counters, etc.
 Explanation using pictorials
 Base10 pictorials, number lines, strip diagrams, etc.
 Strip diagram – a linear model used to illustrate number relationships
 Explanation using number sentences
 Number sentence – a mathematical statement composed of numbers, and/or an unknown(s), and/or an operator(s), and an equality or inequality symbol
 Addition symbol represents joining
 Addend + addend = sum
 Sum = addend + addend
 Subtraction symbol represents separating
 Minuend – subtrahend = difference
 Difference = minuend – subtrahend
 Equal symbol represents a relationship where expressions on each side of the equal sign represent the same value
Note(s):
 Grade Level(s):
 Kindergarten explained the strategies used to solve problems involving adding and subtracting within 10 using spoken words, concrete and pictorial models, and number sentences.
 Grade 2 will add up to four twodigit numbers and subtract twodigit numbers using mental strategies and algorithms based on knowledge of place value and properties of operations.
 Various mathematical process standards will be applied to this student expectation as appropriate.
 TxRCFP:
 Solving problems involving addition and subtraction
 TxCCRS:
 I. Numeric Reasoning
 II.D. Algebraic Reasoning – Representations
 VIII. Problem Solving and Reasoning
 IX. Communication and Representation
 X. Connections

1.3F 
Generate and solve problem situations when given a number sentence involving addition or subtraction of numbers within 20.

Generate, Solve
PROBLEM SITUATIONS WHEN GIVEN A NUMBER SENTENCE INVOLVING ADDITION OR SUBTRACTION OF NUMBERS WITHIN 20
Including, but not limited to:
 Whole numbers
 Counting (natural) numbers – the set of positive numbers that begins at one and increases by increments of one each time {1, 2, 3, ..., n}
 Whole numbers – the set of counting (natural) numbers and zero {0, 1, 2, 3, ..., n}
 Addition
 Sum – the total when two or more addends are joined
 Addend – a number being added or joined together with another number(s)
 Addition of whole numbers within 20
 Subtraction
 Difference – the remaining amount after the subtrahend has been subtracted from the minuend
 Minuend – a number from which another number will be subtracted
 Subtrahend – a number to be subtracted from a minuend
 Subtraction of whole numbers within 20
 Number sentence – a mathematical statement composed of numbers, and/or an unknown(s), and/or an operator(s), and an equality or inequality symbol
 Number sentences, or equations, with an equal sign at the beginning or end
 Unknown in any position
 Generate and solve mathematical and realworld problem situations when given an addition number sentence.
 Appropriate mathematical language
 Connection between information in the problem and problem type
 Addition situations
 Joining action result unknown
 Joining action change unknown
 Joining action start unknown
 Partpartwhole whole unknown
 Partpartwhole part unknown
 Additive comparison difference unknown
 Additive comparison compare quantity (larger quantity) unknown
 Generate and solve mathematical and realworld problem situations when given a subtraction number sentence.
 Appropriate mathematical language
 Connection between information in the problem and problem type
 Subtraction situations
 Separating action result unknown
 Separating action change unknown
 Separating action start unknown
 Partpartwhole part unknown
 Additive comparison difference unknown
 Additive comparison referent (smaller quantity) unknown
Note(s):
 Grade Level(s):
 Grade 1 introduces generating and solving problem situations when given a number sentence involving addition and subtraction of whole numbers within 20.
 Grade 2 will generate and solve problem situations for a given mathematical number sentence involving addition and subtraction of whole numbers within 1,000.
 Various mathematical process standards will be applied to this student expectation as appropriate.
 TxRCFP:
 Solving problems involving addition and subtraction
 TxCCRS:
 I. Numeric Reasoning
 II.D. Algebraic Reasoning – Representations
 VIII. Problem Solving and Reasoning
 IX. Communication and Representation
 X. Connections

1.5 
Algebraic reasoning. The student applies mathematical process standards to identify and apply number patterns within properties of numbers and operations in order to describe relationships. The student is expected to:


1.5D 
Represent word problems involving addition and subtraction of whole numbers up to 20 using concrete and pictorial models and number sentences.

Represent
WORD PROBLEMS INVOLVING ADDITION AND SUBTRACTION OF WHOLE NUMBERS UP TO 20 USING CONCRETE AND PICTORIAL MODELS AND NUMBER SENTENCES
Including, but not limited to:
 Whole numbers
 Counting (natural) numbers – the set of positive numbers that begins at one and increases by increments of one each time {1, 2, 3, ..., n}
 Whole numbers – the set of counting (natural) numbers and zero {0, 1, 2, 3, ..., n}
 Addition
 Sum – the total when two or more addends are joined
 Addend – a number being added or joined together with another number(s)
 Addition of whole numbers within 20
 Subtraction
 Difference – the remaining amount after the subtrahend has been subtracted from the minuend
 Minuend – a number from which another number will be subtracted
 Subtrahend – a number to be subtracted from a minuend
 Subtraction of whole numbers within 20
 Represent mathematical and real world problem situations
 Concrete models
 Objects represent the quantities described in the problem situation.
 Base10 blocks, linking cubes, counters, etc.
 Pictorial models
 Pictures drawn represent the quantities described in the problem situation.
 Base10 pictorials, number lines, strip diagrams, etc.
 Solutions recorded with a number sentence
 Number sentence – a mathematical statement composed of numbers, and/or an unknown(s), and/or an operator(s), and an equality or inequality symbol
 Numbers represent the quantities described in the problem situation.
 Number sentences, or equations, with an equal sign at the beginning or end
 Unknown in any position
 Oral and written descriptions
 Explanation of relationship between objects, pictorials, and numbers and the information in the problem situation
 Addition problem types
 Joining action result unknown
 Joining action change unknown
 Joining action start unknown
 Partpartwhole whole unknown
 Partpartwhole part unknown
 Additive comparison difference unknown
 Additive comparison compare quantity (larger quantity) unknown
 Subtraction problem types
 Separating action result unknown
 Separating action start unknown
 Separating action change unknown
 Partpartwhole part unknown
 Additive comparison difference unknown
 Additive comparison referent (smaller quantity) unknown
Note(s):
 Grade Level(s):
 Grade 1 introduces representing word problems involving addition and subtraction of whole numbers up to 20 using concrete and pictorial models and number sentences.
 Grade 2 will represent and solve addition and subtraction word problems where unknowns may be any one of the terms in the problem.
 Various mathematical process standards will be applied to this student expectation as appropriate.
 TxRCFP:
 Solving problems involving addition and subtraction
 TxCCRS:
 I. Numeric Reasoning
 II.D. Algebraic Reasoning – Representations
 VIII. Problem Solving and Reasoning
 IX. Communication and Representation
 X. Connections

1.5E 
Understand that the equal sign represents a relationship where expressions on each side of the equal sign represent the same value(s).

Understand
THE EQUAL SIGN REPRESENTS A RELATIONSHIP WHERE EXPRESSIONS ON EACH SIDE OF THE EQUAL SIGN REPRESENT THE SAME VALUE(S)
Including, but not limited to:
 Term – a number and/or an unknown in an expression separated by an operation symbol(s)
 Expression – a mathematical phrase, with no equal sign or comparison symbol, that may contain a number(s), an unknown(s), and/or an operator(s)
 Equal sign – a mathematical symbol representing equivalence
 Equation – a mathematical statement composed of equivalent expressions separated by an equal sign
 Multistep solutions represented with one number sentence, or equation, per step
 All expressions separated by equal signs must be equivalent.
 Equal sign does not necessarily mean “find the answer”
 Equations with operations on both sides of the equal sign
 Equations with the unknown in any position
Note(s):
 Grade Level(s):
 Grade 1 introduces an understanding that the equal sign represents a relationship where expressions on each side of the equal sign represent the same value(s).
 Grade 2 will represent and solve addition and subtraction word problems where unknowns may be any one of the terms in the problem.
 Various mathematical process standards will be applied to this student expectation as appropriate.
 TxRCFP:
 Solving problems involving addition and subtraction
 TxCCRS:
 II.D. Algebraic Reasoning – Representations
 IX. Communication and Representation

1.5F 
Determine the unknown whole number in an addition or subtraction equation when the unknown may be any one of the three or four terms in the equation.

Determine
THE UNKNOWN WHOLE NUMBER IN AN ADDITION OR SUBTRACTION EQUATIONWHEN THE UNKNOWN MAY BE ANY ONE OF THE THREE OR FOUR TERMS IN THE EQUATION
Including, but not limited to:
 Whole numbers
 Counting (natural) numbers – the set of positive numbers that begins at one and increases by increments of one each time {1, 2, 3, ..., n}
 Whole numbers – the set of counting (natural) numbers and zero {0, 1, 2, 3, ..., n}
 Addition
 Sum – the total when two or more addends are joined
 Addend – a number being added or joined together with another number(s)
 Addition of whole numbers within 20
 Subtraction
 Difference – the remaining amount after the subtrahend has been subtracted from the minuend
 Minuend – a number from which another number will be subtracted
 Subtrahend – a number to be subtracted from a minuend
 Subtraction of whole numbers within 20
 Term – a number and/or an unknown in an expression separated by an operation symbol(s)
 Expression – a mathematical phrase, with no equal sign or comparison symbol, that may contain a number(s), an unknown(s), and/or an operator(s)
 Equal sign – a mathematical symbol representing equivalence
 Equation – a mathematical statement composed of equivalent expressions separated by an equal sign
 Fact families – related number sentences using the same set of numbers
 a + b = c b + a = c
c – a = b c – b = a
 Strategies for determining an unknown when the unknown may be any one of the three terms in the equation
 Relationship between the parts and the whole
 Balance the expressions on each side of the equal sign
 Connection to understanding that the equal sign represents a relationship where expressions on each side of the equal sign represent the same value(s)
 Use a related fact family equation
 Strategies for determining an unknown when the unknown may be any one of the four terms in the equation
 Add or subtract known terms on each side of the equal sign to create a three term equation, then determine the unknown
Note(s):
 Grade Level(s):
 Grade 1 introduces determining the unknown whole number in an addition or subtraction equation when the unknown may be any one of the three or four terms in the equation.
 Grade 2 will represent and solve addition and subtraction word problems where unknowns may be any one of the terms in the problem.
 Various mathematical process standards will be applied to this student expectation as appropriate.
 TxRCFP:
 Solving problems involving addition and subtraction
 TxCCRS:
 I. Numeric Reasoning
 II.D. Algebraic Reasoning – Representations
 VIII. Problem Solving and Reasoning
 IX. Communication and Representation

1.5G 
Apply properties of operations to add and subtract two or three numbers.

Apply
PROPERTIES OF OPERATIONS TO ADD AND SUBTRACT TWO OR THREE NUMBERS
Including, but not limited to:
 Whole numbers
 Counting (natural) numbers – the set of positive numbers that begins at one and increases by increments of one each time {1, 2, 3, ..., n}
 Whole numbers – the set of counting (natural) numbers and zero {0, 1, 2, 3, ..., n}
 Addition
 Sum – the total when two or more addends are joined
 Addend – a number being added or joined together with another number(s)
 Addition of whole numbers within 20
 Subtraction
 Difference – the remaining amount after the subtrahend has been subtracted from the minuend
 Minuend – a number from which another number will be subtracted
 Subtrahend – a number to be subtracted from a minuend
 Subtraction of whole numbers within 20
 Recognition of addition and subtraction as inverse operations
 Fact families – related number sentences using the same set of numbers
 Additive identity – the sum/difference is not affected when zero is added/subtracted to a number
 Commutative property of addition – if the order of the addends are changed, the sum will remain the same
 Two addends
 Three addends
 Subtraction is not commutative even though addition is commutative.
 Associative property of addition – if three or more addends are added, they can be grouped in any order, and the sum will remain the same
 Two addends
 Hidden tens
 Decompose an addend to form a tens fact.
 Hidden doubles
 Decompose an addend to form a doubles fact.
 Three addends
 Modeling properties of operations to add and subtract two or three numbers
Note(s):
 Grade Level(s):
 Grade 1 introduces applying properties of operations to add and subtract two or three numbers.
 Various mathematical process standards will be applied to this student expectation as appropriate.
 TxRCFP:
 Solving problems involving addition and subtraction
 TxCCRS:
 I. Numeric Reasoning
 IX. Communication and Representation
