OREGON MATH STANDARDS (2021): [1.NBT]
Overview
The intent of clarifying statements is to provide additional guidance for educators to communicate the intent of the standard to support the future development of curricular resources and assessments aligned to the 2021 math standards.
Clarifying statements can be in the form of succinct sentences or paragraphs that attend to one of four types of clarifications: (1) Student Experiences; (2) Examples; (3) Boundaries; and (4) Connection to Math Practices.
2021 Oregon Math Guidance: 1.NBT.A.1
Cluster: 1.NBT.A - Extend the counting sequence.
STANDARD: 1.NBT.A.1
Standards Statement (2021):
Count to 120, starting at any number less than 120. In this range, read and write numerals and represent a number of objects with a written numeral.
Connections:
Preceding Pathway Content (2021) | Subsequent Pathway Content (2021) | Cross Domain Connections (2021) | Common Core (CCSS) (2010) |
K.NCC.A.1 | 1.NBT.B.2 | N/A | 1.NBT.A.1 1.NBT.A Crosswalk |
Standards Guidance:
Clarifications
- Students should understand that as the counting sequence increases, the value of each number increases by one or ten. As the counting sequence decreases, the value of each number decreases by one or ten.
- Count forward and backward, starting at any number less than 120.
Teaching Strategies
- Students should count forwards and backwards by 1s and 10s from any number within 120.
- Skip count by twos to 20, by fives to 100, and by tens to 120.
- Students should have opportunities to explore the counting sequences using a variety of tools. These tools can include, but are not limited to 99 charts, hundred charts, number paths,
number lines (predetermined and open), etc.
Examples
- Understand that two digit numbers are composed of tens and ones.
- Understand that 3 digit numbers are composed of hundreds, tens, and ones.
- Understand that numbers increase in consistent patterns because of the place value system.
- Illustrative Mathematics:
- Student Achievement Partners
2021 Oregon Math Guidance: 1.NBT.B.2
Cluster: 1.NBT.B - Understand place value.
STANDARD: 1.NBT.B.2
Standards Statement (2021):
Understand 10 as a bundle of ten ones and that the two digits of a two-digit number represent amounts of tens and ones.
Connections:
Preceding Pathway Content (2021) | Subsequent Pathway Content (2021) | Cross Domain Connections (2021) | Common Core (CCSS) (2010) |
K.NBT.A.1, 1.NBT.A.1 | 1.NBT.B.3, 1.NBT.C.4, 1.NBT.C.5, 1.NBT.C.6, 2.NBT.A.1 | N/A | 1.NBT.B.2 1.NBT.B Crosswalk |
Standards Guidance:
Clarifications
- Students should be able to recognize the relationship of a digit to its place indicates the number of groups represented in that place. For example: In the number 33, the digit “3” in the tens place has a value that is equivalent to three groups of ten. Students interpret the value of each digit. The number 33 has three tens and three remaining ones. They should also see this as equivalent to 33 ones.
- Students should understand the following as special cases:
- 10 can be thought of as a bundle of ten ones — called a “ten.” Bundles could include groups of pennies, bundles of straws, or other hands-on manipulatives.
- The numbers from 11 to 19 are composed or decomposed as a ten and one, two, three, four, five, six, seven, eight, or nine ones.
Boundaries
- Students should be able to explain that the numbers 10, 20, 30, 40, 50, 60, 70, 80, 90 refer to one, two, three, four, five, six, seven, eight, or nine tens (and 0 ones).
Teaching Strategies
- The numbers 11 to 19 can be represented on ten frames, double ten frames, rekenreks, and with pennies and dimes, etc.
- The numbers 10, 20, 30, 40, 50, 60, 70, 80, and 90, can be represented using a variety of tools (popsicle sticks, linking cubes, straws, etc.)
Progressions
- First graders learn that the two digits of a two-digit number represent amounts of tens and ones, e.g., 67 represents 6 tens and 7 ones. Saying 67 as "6 tens, 7 ones" as well as "sixty-seven" can help students focus on the tens and ones structure of written numerals. (Please reference page 6 in the Progression document).
Example
- Illustrative Mathematics:
- Student Achievement Partners:
2021 Oregon Math Guidance: 1.NBT.B.3
Cluster: 1.NBT.B - Understand place value.
STANDARD: 1.NBT.B.3
Standards Statement (2021):
Compare two two-digit numbers based on meanings of the tens and ones digits, recording the results of comparisons with the symbols >, =, and <.
Connections:
Preceding Pathway Content (2021) | Subsequent Pathway Content (2021) | Cross Domain Connections (2021) | Common Core (CCSS) (2010) |
K.NCC.B.5, K.NCC.C.7, 1.NBT.B.2 | 2.NBT.A.4 | N/A | 1.NBT.B.3 1.NBT.B Crosswalk |
Standards Guidance:
Clarifications
- Students should understand whole numbers to 100 based on meanings of the tens and ones and record the results of comparisons with the symbols >, =, and <.
Boundaries
- Students should have ample experiences communicating their comparisons using words, models AND context before using only symbols in the learning objective.
- Students need practice justifying comparisons with words and models, prior to exposure and use of the comparison symbols.
Teaching Strategies
- Representations should include the use of physical materials such as number paths, base-ten materials, number lines (predetermined and open), dimes and pennies, etc.
Progressions
- Grade 1 students use their base-ten work to help them recognize that the digit in the tens place is more improtant for determining the size of a two-digit number.
- Correctly placing the < and > symbols is a challenge for early learners. Accuracy can improve if students think of putting the wide part of the symbol next to the larger number. (Please reference page 6 in the Progression document).
Examples
- Students should be given the opportunity to provide explanations of their results based on their understanding of place value.
- 2 tens + 9 ones < 3 tens + 2 ones
- 2 tens and 9 ones < 92
- Understand that a greater value in a given place supersedes any amount in a place with a smaller value.
- Illustrative Mathematics:
2021 Oregon Math Guidance: 1.NBT.C.4
Cluster: 1.NBT.C - Use place value understanding and properties of operations to add and subtract.
STANDARD: 1.NBT.C.4
Standards Statement (2021):
Add within 100 using concrete or visual representations and strategies based on place value, properties of operations, and/or the relationship between addition and subtraction. Relate the strategy to a written method and explain why sometimes it is necessary to compose a ten.
Connections:
Preceding Pathway Content (2021) | Subsequent Pathway Content (2021) | Cross Domain Connections (2021) | Common Core (CCSS) (2010) |
1.NBT.B.2 | 2.NBT.B.5 | 1.OA.C.6, 2.OA.A.1 | 1.NBT.C.4 1.NBT.C Crosswalk |
Standards Guidance:
Clarifications
- Students should be able to interpret and manipulate concrete mathematical models.
- Students should be given opportunities to justify their solutions to meet this learning objective.
- Students should use estimation as a strategy to find numbers that are close to the numbers they are using to add and subtract.
- The numerical reasoning developed should include an understanding of the base-ten structure and properties of operations.
- Students should reason that in adding two-digit numbers, one adds tens and tens, ones and ones; and sometimes it is necessary to put together (compose) or break apart (decompose) a ten.
Terminology
- The terms below are used to clarify expectations for the teaching professional. Students are not required to use this terminology when engaging with the learning objective.
- Compose – put together numbers
- Decompose – break apart numbers
- Estimate – find a value that is close
Boundaries
- The properties of operation that should be explored in this objective are the commutative and associative properties. Students are not expected to identify properties.
Teaching Strategies
- Students should use concrete models, drawings, estimation, and strategies based on place value, properties of operations, and/or the relationship between addition and subtraction to explain their reasoning.
- Strategies may include reasoning involving making a ten, doubles and near-doubles, think addition, and using benchmark numbers.
Examples
- Illustrative Mathematics:
- Student Achievement Partners:
2021 Oregon Math Guidance: 1.NBT.C.5
Cluster: 1.NBT.C - Use place value understanding and properties of operations to add and subtract.
STANDARD: 1.NBT.C.5
Standards Statement (2021):
Without having to count, mentally find 10 more or 10 less than a given two-digit number and explain the reasoning used.
Connections:
Preceding Pathway Content (2021) | Subsequent Pathway Content (2021) | Cross Domain Connections (2021) | Common Core (CCSS) (2010) |
1.NBT.B.2 | 2.NBT.B.5 | 2.OA.A.1 | 1.NBT.C.5 1.NBT.C Crosswalk |
Standards Guidance:
Boundaries
- This expectation requires students to apply this mental strategy and become fluent through purposeful practice. The goal is automaticity built on a deep understanding of the patterns of tens within our base-ten system.
Examples
- Find 10 more than a given two digit number, for example 34 + 10.
- Find 10 less than a given two digit number, for example 34-10.
- Understand that adding or subtracting multiples of 10 from a number changes only the tens digit because the addition or subtraction changes only the quantity of tens.
- There were 74 birds in the park. 10 of the birds flew away. How many birds are in the park, now?
- I pictured 7 ten-frames and 4 left over in my head. Since 10 birds flew away, I took one of the ten-frames away. That left 6 ten-frames and 4 left over. So, there are 64 birds left in the park.
- Illustrative Mathematics:
2021 Oregon Math Guidance: 1.NBT.C.6
Cluster: 1.NBT.C - Use place value understanding and properties of operations to add and subtract.
STANDARD: 1.NBT.C.6
Standards Statement (2021):
Subtract multiples of 10 in the range 10-90 from multiples of 10 in the range 10-90 using concrete or visual representations and strategies based on place value, properties of operations, and/or the relationship between addition and subtraction. Relate the strategy and model used to a written method and explain the reasoning used.
Connections:
Preceding Pathway Content (2021) | Subsequent Pathway Content (2021) | Cross Domain Connections (2021) | Common Core (CCSS) (2010) |
1.NBT.B.2 | 2.NBT.B.5 | 2.OA.A.1 | 1.NBT.C.6 1.NBT.C Crosswalk |
Standards Guidance:
Boundaries
- By the end of first grade, students should be able to state and write their justifications showing the relationship between their solution path and their reasoning. The focus of this standard is on thought processes, not merely on computational accuracy.
Teaching Strategies
- Students should use concrete models; drawings, and strategies based on place value, properties of operations, and or/the relationship between addition and subtraction to explain their reasoning.
- Students should describe sums and differences, using concrete models (tools and manipulatives), drawings, and strategies based on place value, properties of operations and/or the relationship between addition and subtraction to explain (verbally and/or written) the reasoning used.
Progressions
- Differences of multiples of 10, such as 70 – 40 can be viewed as 7 tens minus 4 tens and represented with concrete models such as objects bundled in tens or drawings.
- Students use the relationship between subtraction and addition when they view 80 – 70 as an unknown addend addition problem, 70 + <box> = 80, and reason that 1 ten must be added to 70 to make 80, so 80 –70 = 10. (Please reference page 7 in the Progression document).
Examples
- Represent subtraction of multiples of 10 with concrete and/or visual models based on place value. For example, represent 30 as 3 groups of ten and no ones.
- Understand that the inverse relationship between subtraction and addition exists because both are different representations of the same part-part-whole relationship. For example, understand that both 20+30=50 and 50-20=30 represent the same parts and whole.
- Student Achievement Partners: