Partnering Addition and Multiplication
- Students will use repeated addition to solve multiplication problems.
- Introduce the lesson by inviting students to participate in an addition challenge.
- Distribute individual whiteboards and whiteboard markers.
- Tell students that you will hold up a doubles multiplication problem. Their task is to write the answer on their whiteboards as fast as they can and to hold up their whiteboards to show you the answer.
- One by one, hold up each flash card and give students a chance to show what they know by writing the answer on their whiteboards. Guide students in making connection by having them reflect on why doubles are easier.
- Tell the students that they will be learning about how to use repeated addition to solve multiplication problems, just like when one number is doubled to make a doubles fact.
Explicit Instruction/Teacher modeling(10 minutes)
- Invite students to make a semicircle so that they can see the objects that you place in the middle.
- Tell the students that addition and multiplication are related.
- Explain that multiplication problems can be solved by creating equal groups and adding those groups together using repeated addition.
- Take out a set of objects such as crayons.
- Write the following problem (or other problem of choice) on the board: 5 X 3
- Tell the students that you can make five groups of three to solve this problem.
- Explain that you can suggest that students use skip counting to find the product, or total.
- Show your work on the board so that students can see that 5 X 3 can mean five groups of three and 3 + 3 + 3 + 3 + 3 = 15.
- Continue to model with other multiplication problems, as needed.
Guided practise(10 minutes)
- Tell the students that they are going to get an opportunity to act out several additional multiplication problems.
- Write the following problem on the board: 5 X 2
- Invite ten students to model the problem by standing in five groups of two. Point out that students can also make two groups of five.
- Ask the class how they can use repeated addition to find the answer to the problem.
- Guide the students in solving the problem.
- Distribute individual whiteboards and markers and ask the students to draw repeated addition groups and solve the problem, 7 X 2
- Monitor student work, guiding students, and providing additional support and problems as needed.
Independent working time(15 minutes)
- Distribute white construction paper and stickers, stamps, or Do-a-Dot markers so that each student has one piece of paper and other available materials.
- Write a selection of multiplication problems on the board that the students can solve by creating equal groups and using repeated addition.
- Ask students to create groups with their stickers, stamps, or markers and to solve the problems.
- Rotate around the room as students are working to assist, as needed.
- Challenge students with more complex problems that involve a combination of two digit by one digit multiplication problems.
- Invite students to create their own one-digit-by-one-digit multiplication problems and trade with a partner to find the answer.
- If students struggle with using two-dimensional representations, allow students to use counters or two-sided chips to work out the problems.
- Invite students to create explanations or examples of how repeated addition is used to solve multiplication problems. Give students the opportunity to use the format of their choice (such as Google Drawings, VoiceThread, etc.) to create their examples and explanations.
- Ask the students to complete the Partner Up worksheet.
Review and closing(5 minutes)
- Ask students to turn to a partner and share or write a response in their journals, responding to the following question: How are addition and multiplication related? How can we use addition to solve multiplication problems?