Choose Addition or Subtraction

Overview

In this 30-minute small-group lesson, students identify whether a real-life story problem requires addition or subtraction. Students connect action words and picture models to operation symbols, then solve problems using counters, drawings, or equations. This is Lesson 16 of 18 in Math Explorers: Measure, Graph, Solve and builds on prior work solving addition and subtraction problems within 100.

Learning intentions

Students will be able to:

• Identify the action in a story problem.
• Choose addition or subtraction to match the action.
• Model a problem with counters, a drawing, or an equation.
• Explain how words such as “more,” “left,” and “altogether” help identify the operation.

Success criteria

• I can identify what happens in the story.
• I can choose the correct operation symbol, + or −.
• I can model and solve the problem.
• I can solve at least 4 of 5 problems correctly.

Curriculum links

• Georgia Mathematics: identify the operation needed in real-life addition and subtraction situations.
• Measurement and Data: solve word problems involving lengths or quantities in the same units using addition and subtraction.
• Mathematical Practices: make sense of problems, use tools strategically, and explain thinking with models, words, or equations.

Lesson structure (30 minutes)

1. 0–4 min · Hook and learning intention. Teacher opens the hook and learning intention slides, displays “I can choose addition or subtraction to solve a story problem,” and acts out placing 5 apples on a table before adding 3 more. Students watch, describe what changed, and choose whether the group became larger or smaller.

2. 4–9 min · Direct teach: addition. Teacher acts out the story “There are 5 apples and 3 more join,” places 5 and then 3 counters, and records 5 + 3 = 8; emphasize that “more join” means the amount increases. Students use counters to copy the action and say, “I add because more joined.”

3. 9–13 min · Direct teach: subtraction. Teacher acts out “There are 8 apples and 3 are eaten,” removes 3 counters, and records 8 − 3 = 5; connect “eaten,” “go away,” and “left” to subtraction. Students model the story and complete the sentence, “I subtract because some went away.”

4. 13–19 min · We do: choose and model. Teacher displays picture stories from the operation sorting and modeling slides and gives students + and − operation cards. For each story, read the text aloud, ask “What action happened?” and support students to place the correct card, then move counters to show the action. Students take turns choosing + or −, modeling with counters, and explaining their choice using “I chose ___ because ___.”

5. 19–26 min · You do: guided independent practice. Teacher distributes the picture-supported operation practice worksheet and reads each of three problems aloud, one at a time. Students solve using counters, drawings, or equations; teacher prompts without naming the operation: “Did the amount grow, or did some go away?” Confer briefly with each student and record whether the student identified the action, selected the symbol, modeled, and solved.

6. 26–30 min · Check and close. Teacher gives the five-question check shown in the review and assessment slides or reads it aloud, then asks students to share one clue for addition and one clue for subtraction. Students answer independently, explain one choice, and self-check against the success criteria.

Five-question check

1. “3 more join 4” means: A add, B subtract, C measure.
2. “9 left after 2 go away” means: A add, B subtract, C graph.
3. 6 + 2 =: A 4, B 8, C 12.
4. 10 − 3 =: A 7, B 13, C 3.
5. “Altogether” usually tells us to: A add, B subtract, C compare height.

Resources

• the complete story-problem slide deck
• the picture-supported operation practice worksheet
• Small counters or connecting cubes
• Large + and − operation cards
• Picture cards or simple classroom objects such as paper apples
• Pencils, crayons, and erasers
• Optional AAC device or symbol cards

Assessment

• During modeling and sorting, check whether each student identifies the action, selects + or −, and represents the story accurately.
• Review the three worksheet problems for operation choice, model, equation, and solution; ask students to explain any mismatch.
• Score the five-question check. The target is at least 4 out of 5 correct; reteach using acted-out stories if a student scores below the target.

Differentiation

• Act out every story and use real objects or counters before moving to drawings and equations. Keep numbers within 10 for students who need reduced cognitive load.
• Provide sentence frames: “I chose ___ because ,” “ more means add,” and “___ went away, so I subtract.” Use bold, high-contrast + and − cards.
• Read all text aloud, present one problem per page or screen, use picture-supported directions, and avoid crowded layouts to support students with dyslexia.
• Accept oral responses, pointing, AAC, manipulatives, or drawings instead of requiring written explanations. For extension within the same task, ask a student to create a matching addition or subtraction story for a given equation.