Colorado Academic Standards Online
Use the options below to create customized views of the Colorado Academic Standards. For all standards resources, see the Office of Standards and Instructional Support.
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clear Content Area: Mathematics - 2019 // Grade Level: First Grade // Standard Category: 2. Algebra and Functions
Mathematics - 2019
First Grade, Standard 2. Algebra and Functions
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- MP1. Make sense of problems and persevere in solving them.
- MP4. Model with mathematics.
1.OA.A. Operations & Algebraic Thinking: Represent and solve problems involving addition and subtraction.
Students Can:
- Use addition and subtraction within 20 to solve word problems involving situations of adding to, taking from, putting together, taking apart, and comparing, with unknowns in all positions, e.g., by using objects, drawings, and equations with a symbol for the unknown number to represent the problem. (CCSS: 1.OA.A.1)
- Solve word problems that call for addition of three whole numbers whose sum is less than or equal to 20, e.g., by using objects, drawings, and equations with a symbol for the unknown number to represent the problem. (CCSS: 1.OA.A.2)
Academic Contexts and Connections:
Colorado Essential Skills and Mathematical Practices:
- Make sense of problems by relating objects, drawings, and equations. (MP1)
- Use cubes, number racks, ten frames and other models to represent addition and subtraction situations in real-world contexts. (MP4)
- How can you use cubes to help you compare two numbers?
- (Given a representation of a value less than ten) How many more do you need to make ten?
- This expectation represents major work of the grade.
- In kindergarten, students add and subtract within 10 by using objects or drawings to represent problems.
- In Grade 1, this expectation connects with comparing, adding, and subtracting numbers, including measurement and data activities.
- In Grade 2, students represent and solve real-world problems involving addition and subtraction within 100, with fluency expected within 20.
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- MP1. Make sense of problems and persevere in solving them.
- MP7. Look for and make use of structure.
1.OA.B. Operations & Algebraic Thinking: Understand and apply properties of operations and the relationship between addition and subtraction.
Students Can:
- Apply properties of operations as strategies to add and subtract. (Students need not use formal terms for these properties.) Examples: If 8+3=11 is known, then 3+8=11 is also known. (Commutative property of addition.) To add 2+6+4, the second two numbers can be added to make a ten, so 2+6+4=2+10=12. (Associative property of addition.) (CCSS: 1.OA.B.3)
- Understand subtraction as an unknown-addend problem. For example, subtract 10−8 by finding the number that makes 10 when added to 8. (CCSS: 1.OA.B.4)
Academic Contexts and Connections:
Colorado Essential Skills and Mathematical Practices:
- Make sense of addition and subtraction by applying properties of operations and working with different problem types (see Appendix, Table 1). (MP1)
- Use properties of operations to recognize equivalent forms of equations. (MP7)
- How could you explain why 3+8 and 8+3 both equal 11?
- How can you use the number line to show how you might use adding OR subtracting to solve the same problem?
- This expectation represents major work of the grade.
- In previous grades, students model and describe addition as putting together and adding to, and subtraction as taking apart and taking from, using objects or drawings.
- In Grade 1, this expectation connects with representing and solving problems involving addition and subtraction and with adding and subtracting within 20.
- In future grades, students use place value understanding and properties of operations to add and subtract within larger number ranges, then to perform multi-digit arithmetic. Later, students use these concepts to build fractions from unit fractions, and to apply and extend their understandings of arithmetic to algebraic expressions.
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1.OA.C. Operations & Algebraic Thinking: Add and subtract within 20.
Students Can:
- Relate counting to addition and subtraction (e.g., by counting on 2 to add 2). (CCSS: 1.OA.C.5)
- Add and subtract within 20, demonstrating fluency for addition and subtraction within 10. Use strategies such as counting on; making ten (e.g., 8+6=8+2+4=10+4=14); decomposing a number leading to a ten (e.g., 13−4=13−3−1=10−1=9); using the relationship between addition and subtraction (e.g., knowing that 8+4=12, one knows 12−8=4); and creating equivalent but easier or known sums (e.g., adding 6+7 by creating the known equivalent 6+6+1=12+1=13). (CCSS: 1.OA.C.6)
Academic Contexts and Connections:
Colorado Essential Skills and Mathematical Practices:
- Use multiple strategies to think about problems and see how the quantities involved support the use of some strategies over others. (Entrepreneurial Skills: Critical Thinking/Problem Solving)
- Make use of the structure of numbers when making tens or when creating equivalent but easier or known sums. (MP7)
- Which would you prefer when adding 4+7: starting with 7 and counting up 4 or starting with 4 and counting up 7? Why?
- Why does knowing doubles like 4+4 or 5+5 help when adding 4+5?
- How does counting on to add and subtract within 20 make it easier to use fingers even though we have only 10 fingers?
- This expectation represents major work of the grade.
- In kindergarten, students understand the relationship between numbers and quantities and connect counting to cardinality.
- In Grade 1, this expectation connects with place value understanding, properties of addition and subtraction, the relationship between addition and subtraction, and with representing and solving problems involving addition and subtraction.
- In Grade 2, students fluently add and subtract within 20 using mental strategies and know from memory all sums of two one-digit numbers.
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- MP2. Reason abstractly and quantitatively.
- MP3. Construct viable arguments and critique the reasoning of others.
1.OA.D. Operations & Algebraic Thinking: Work with addition and subtraction equations.
Students Can:
- Understand the meaning of the equal sign, and determine if equations involving addition and subtraction are true or false. For example, which of the following equations are true and which are false? 6=6, 7=8−1, 5+2=2+5, 4+1=5+2. (CCSS: 1.OA.D.7)
- Determine the unknown whole number in an addition or subtraction equation relating three whole numbers. For example, determine the unknown number that makes the equation true in each of the equations 8+?=11, 5=_−3, 6+6=_. (CCSS: 1.OA.D.8)
Academic Contexts and Connections:
Colorado Essential Skills and Mathematical Practices:
- Make sense of quantities and their relationships in problem situations. (MP2)
- Question assumptions about the meaning of the equals sign and construct viable arguments. (MP3)
- What does it mean for two sides of an equation to be “equal”? How can 2+3 “equal” 5?
- (Given 4=4 If you add 2 more to the 4 on the right, how many do you need to add on the left to make a true statement? How would you write that as an equation?
- This expectation represents major work of the grade.
- In kindergarten, students represent addition and subtraction with equations without needing to understand the meaning of the equal sign.
- In Grade 1, this expectation connects with representing and solving problems involving addition and subtraction.
- In Grade 2, students work with equal groups of objects to gain foundations for multiplication. In Grade 4, students build fractions from unit fractions and apply addition and subtraction to concepts of angle and angle measurement.
Need Help? Submit questions or requests for assistance to bruno_j@cde.state.co.us