1.OA.B.4 - About the Math, Learning Targets, and Increasing Rigor

Full Standard

Understand subtraction as an unknown-addend problem. For example, subtract 10 – 8 by finding the number that makes 10 when added to 8.

Measurement Topic

This standard is reported on the report card in these quarters as follows:

About the Math

Skills and concepts below are learning goals for this standard.

• Explain the relationship between addition and subtraction using models and drawings.

It is important for students to share, discuss and compare their strategies as a class. Students will use the relationship between addition and subtraction as a strategy to solve unknown-addend problems. Students naturally connect counting on to solving subtraction problems. For the problem “15 – 7 = ?” they think about the number they have to add to 7 to get to 15. Students can use base ten blocks, ten frames, hundred charts, and number lines to prove that the two operations are related.  First graders should be working with sums and differences less than or equal to 20 using the numbers 0 to 20.

• Represent the relationship between addition and subtraction on a number line or number chart.

Understanding the relationship between addition and subtraction is much more than completing a fact family organizer. Students should prove the relationship by using physical tools and connecting them to hundred charts and number lines.  Provide multiple opportunities for students to study the relationship between addition and subtraction in a variety of ways, including games, modeling and real-world situations.

• Rewrite a subtraction equation as an addition equation with a missing addend.

As students develop an understanding of the relationship between these operations, they should begin to use missing addends to represent subtraction situations. For example, 9 - 7 = ? can be written or thought of as 7 + ? = 9. Students need to understand that addition and subtraction are related, and that subtraction can be used to solve problems where the addend is unknown.

Essential vocabulary for this standard includes: Addition, add, subtraction, subtract, and missing addend.

Progression of Standard within Grade 1

This progression informs how to develop the standard within the grade level. This progression is provided by HCPSS Elementary Mathematics.

Progression of this Standard Across Grades

This progression is informed by the Achieve the Core Coherence Map Links to an external site.. Information is not the complete standard.

TASKS

These tasks can be used with small group or whole group instruction.

• Give each student 20 two-color counters total. Tell them you went apple picking over the weekend and you picked 10 apples. Tell them you picked 7 red apples and the rest were yellow apples. Ask them to work with their partner to figure out how many apples were yellow. As they are trying to figure it out walk around asking questions to each pair such as "How can you use the counters to help you solve this problem? How many apples did I pick in all? How many have to be red? Explain how you figured how yellow apples I picked." After they solve debrief all together and help them come up with matching equations to the problem. Keep working in pairs changing the total number of apples and how many of each color to practice missing addend using the counters to help them visualize the problems. Extension: Tell them you picked some apples and then took them home and your family ate 6. You had 2 apples left in the bag. How many apples did you pick?
• Give the students 20 unifix cubes. Have them each make a tower of 6 cubes. Tell them now you want them to make their tower 11 cubes tall. Ask how many more cubes will you need to add to make your tower 11 cubes tall? Let them work in pairs to figure out how many cubes they need to add on to make their tower 11. Debrief and work together to find the matching equations. Continue practicing making different heights of towers and then asking them to make a larger tower and asking how many they had to add on. Have the students continue to build and write the matching equation(s) for practice. Connect to the word difference as you are solving for how many more to add to make your new tower.
• Sarah picked three apples from the tree. Sarah needs 15 apples in all. How many more apples does Sarah need to pick?
• There were 12 children on the swim team. Four of them were boys and some were girls. How many girls were on the swim team?
• The zoo keeper gave some bananas to the monkeys for lunch. The monkeys ate 7 bananas and the zoo keeper counted 8 left. How many bananas did the zoo keeper start with?
• Marty has 9 books in his library. He wants to have 18. How many more books does Marty need to get?
• Ms. Smith has 17 stamps left in her book of 20. How many stickers did she use?

SLIDE-BASED TASKS 

  These links are HCPSS created instructional tasks. These tasks are provided in Google slides.  These tasks should be used for inspiration and resources, but instruction should start with students having the opportunity to engage with the math first (often involving physical and/or visual models) followed by discussion and explicit instruction to ensure student understanding.

Additional Tasks 

  These links provide instructional ideas connected to this standard. [NOTE: NCTM membership required for access to Illuminations lessons.]

• Cave Game Subtraction Links to an external site. (Illustrative Math)
• Fact Families Links to an external site. (Illustrative Math)
• Fact Families with Pictures Links to an external site. (Illustrative Math)
• A Sense of Ten Links to an external site. (Nrich Math Lesson)
• Puppies Download Puppies
  (Utah Core Academy Lesson)
• Fun on the Playground Download Fun on the Playground
  (Utah Core Academy Lesson)
• Cookie Subtraction Download Cookie Subtraction
  (Utah Core Academy Lesson)
• Frogs on Logs Download Frogs on Logs
  (Utah Core Academy Lesson)
• Zookeeper Download Zookeeper
  (Utah Core Academy Lesson)
• Try For Five Links to an external site. (NCTM Illuminations Lesson)  
• Fact Family Fun Links to an external site. (NCTM Illuminations Lesson)
• How Many Left? Links to an external site. (NCTM Illuminations Lesson)
• Finding Fact Families Links to an external site. (NCTM Illuminations Lesson)
• Macaroni Math Links to an external site. (NCTM Illuminations Lesson)
• Detectives are on the hunt for parts of 6 and 7! Links to an external site. (NCTM Illuminations Lesson)

Tasks From Print Resources

  These publications have been provided for each school. They are typically stored in team closets or the media center. Check with your team leader if you cannot find them. 

Print Resources

Book Thumbnail	Book Title	Grade	Pages
	Teaching Student-Centered Mathematics	K-3	Missing-Part Subtraction, Activity 3.2, Page 74
	Math Intervention-Building Number Power	PreK-2	(115--117)

Centers

  These print resources can be used during independent or center time. These resources could also be used as lesson seeds.

• Selling Strawberries Download Selling Strawberries
   (HCPSS-adapted resource)
• Take Away Ten Download Take Away Ten
   (HCPSS-adapted resource)
• Equation Match Links to an external site.

Independent Practice/HOmEWoRK/Assessment

  These resource sheets can be used for independent practice, homework, or assessment. They are intended to reinforce procedures and concepts. They should not be used as a source of direct instruction or whole-group practice.

• Represent Subtraction as an Unknown Addend a Links to an external site.
• Represent Subtraction as an Unknown Addend b Links to an external site.
• Represent Subtraction as an Unknown Addend c Links to an external site.
• Identify Addition Equations with Missing Addend as Rewritten Subtraction Equations (±2) Links to an external site.
• Represent an Unknown Part Situation as Addition and Subtraction Equations (±2) Links to an external site.
• Explain how Addition Can Represent a Subtraction Situation (Making 10) Links to an external site.
• Use Drawing and Subtraction Equation to Represent an Unknown Part Situation (Making 10) Links to an external site.
• Explain how Addition and Subtraction can be used to Solve Word Problems (Making 10) Links to an external site.
• Represent and Explain the Relationship Between Addition and Subtraction (Doubles) Links to an external site.
• Explain how Addition Can  Represent a Subtraction Situation (Add 10) Links to an external site.
• Explain how Addition and Subtraction can be used to Solve Word Problems (Add 10) Links to an external site.
• Represent and Explain the Relationship Between Addition and Subtraction (Add 10) Links to an external site.

Full Standard

Understand subtraction as an unknown-addend problem. For example, subtract 10 – 8 by finding the number that makes 10 when added to 8.

Measurement Topic

The standard is reported on the report card through these measurement topics. Expand the measurement topic for a description of what students who meet expectation are able to do.

First Grade Students Learning First Grade Standards by Measurement Topic

Kindergarten Students Learning 1st Grade Standards by Measurement Topic

1OA4 Anecdotal Data Collection Tool Links to an external site.

Visit the SBIR (Standards Based Instruction and Reporting) page in Course Essentials for more information and clarification. 

Rubric (for thinking and reasoning evidence)

Use this rubric for observation and constructed responses (tasks that require explanation, justification, and/or representation).

Rubric for Tasks (pdf) Links to an external site.

Exemplars for this standard (if available)

These samples are examples of what it might look like for a student who MEETS EXPECTATIONS, is MAKING PROGRESS, and/or is MAKING LIMITED/NO PROGRESS.