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Students will be able to find an unknown number in an addition word problem.
- Write a story problem up on the board. Read it aloud to your students. For example: "There are 20 animals in the tree. There 10 are snakes, and the rest are monkeys. How many monkeys are in the tree?"
- Write out a corresponding equation to go with the word problem. For the problem above, write out: 10 + ____ = 20.
- Ask them to turn and talk with a partner to share how they could solve this problem.
- Provide students with visuals that connect to the word problem.
- Pair students with a partner who speaks the same home language (L1), if possible.
- Encourage students to rephrase the story problem in their own words to a partner to check for understanding.
- Provide students with sentence stems, such as:
- I can solve the problem by ____.
- A strategy I can use is ____.
Explicit Instruction/Teacher modeling(5 minutes)
- Have a few pairs share their thinking with the class.
- Using their ideas, solve the problem on the board. Include drawings and an equation to demonstrate how you can double-check your answer in multiple ways.
- Explain that sometimes in an equation or math problem we know some parts of the equation, but other parts might be missing. We call the missing pieces the unknown numbers.
- Give students a glossary that has important words from the lesson and corresponding visuals in English and their home language (L1).
- Ask students to come up to the whiteboard to point to the line that represents the term unknown numbers in the equation. Have students orally share the vocabulary word as they point.
- Instruct students to turn and talk to an elbow partner, explaining unknown numbers in their own words.
Guided Practice(10 minutes)
- Write a second problem on the board. For example: "There are 25 kids in the class. 15 kids have red shoes, and the rest of the kids have blue shoes. How many kids have blue shoes?"
- Copy out the corresponding equation on the board: 15 + ____ = 25.
- Pass out paper to each student and have them work in pairs to solve the problem.
- Invite one or two pairs to share their work with the class.
- Clarify any teaching points and answer questions as needed.
- Provide students with visuals of shoes for context.
- Encourage students to detail their process using a sentence frame for support (e.g. "I know ____ kids have blue shoes because ____.")
- Allow students to show/refer to their visual representation as they share out their work with the class.
- Have students explain the story problem in their own words to their partner prior to solving the problem.
Independent working time(15 minutes)
- Explain that your students will now complete the What’s Missing worksheet to practice finding the unknown number in each equation.
- As students finish the worksheet, provide them with blank paper and encourage them to create their own story problem and unknown number equation to trade with a partner.
- Offer support to your students as needed.
- Allow students to work in a small, teacher-led group or with a group of students who speak the same home language (L1).
- Allow students to include images to support their word problem writing.
- Provide a paragraph frame for students to support their writing.
- Allow students to work in partnerships.
- Encourage them to discuss their reasoning and share whether they agree or disagree with their partner.
- Provide math manipulatives for students to use when figuring out the unknown numbers.
- Have students create two or more story problems featuring a missing number for a peer to complete.
- Pass out the Unknown Numbers worksheet for additional practice.
- Collect student worksheets and assess whether they were able to find the correct unknown numbers in each problem.
- Assess whether students were able to solve their classmates' problems.
- Encourage students to detail their process using a sentence frame, such as: "I know ____ because ____."
- Encourage students to explain the strategy they used to solve the problem to their partner.
Review and closing(5 minutes)
- Share 1–2 problems created by students with the class. Work together as a group to solve each problem.
- Answer questions as needed.
- Have students share their answers with a peer who speaks the same home language, if possible.
- Provide sentence stems and frames as needed.