Lesson Title: Let’s Multiply!

Creator: Lauren Jarroll

Grade Level: Third

Big Idea: Writing Across the Curriculum: Multiplication Stories

Essential Question:

Why is it important to learn basic multiplication facts?

How can multiplication be used to solve real life problems?

CSOs, Learning Skills, Technology Tools:

M.O.3.1.9: The students will demonstrate and model multiplication (repeated addition, arrays) and division (repeated subtraction, partitioning).

M.O.3.1.11: The students will recall basic multiplication facts and the corresponding division facts.

M.O.3.1.14: The students will create grade appropriate real world problems involving any of the four operations using multiple strategies, explain the reasoning used, and justify the procedures selected when presenting solutions.

21C.O.3-4.3LS.4: Students appreciates, accepts, and works cooperatively with others, in both academic and social contexts, shares responsibility for continued improvement of the academic performance and climate of the school, and exhibits ethical behavior while working alone or communicating with others.

21.C.O.3-4.2TT.3: Students use technology tools (e.g. presentation software, word processing software, group web page design, digital cameras, scanners) for individual and collaborative writing, communication, and publishing activities to create informative products for audiences inside and outside the classroom.

21C.0.3-4.2TT.4: Students use technology tools (eg. calculators, data collection probes, videos, educational software) for problems solving, self-directed learning, and extended learning activities.

21C.O.3-4.3TT.6: Students select appropriate technology tools and resources needed to communicate information to others, to achieve personal goals, and to support independent learning.

Introduction:

Activate Prior Knowledge: whole group activity

Review skip counting with the class. Begin by counting by 2, 5, and 10, then include 3s and 4s. Review the word “multiples” and ask if anyone can explain how skip counting and multiples are related.

Brainstorming: Ask children to think of things that come in groups of 2. List items on the chalkboard, giving help as needed (eyes, feet, twins, sleeves, etc.). Then choose one listed item, such as feet, and ask the children how many feet two people have. Continue to ask students: How many feet four people have?, the girls or boys have?, how many feet are in the classroom?, etc. As the children answer, encourage them to explain how they have solved the problem. Review the words “factor” and “product”, explaining that factors are numbers that we multiply to equal a product or the answer. In counting feet, the factors would be 2 (the number of feet), and the number of people; while the product would be the total number of feet.

Specialized Vocabulary Development: Multiples, factors, and product are multiplication vocabulary words that can be introduced and reviewed during the lesson introduction. Arrays and equal groups will be presented during the lesson investigation. Teacher- made vocabulary cards can be displayed as the words are used in the lesson.

Investigate/Explore:

Small group activity: 3-4 children in each group

Ask the children to list items for other numbers. Children will work in small groups to think of objects that come in threes, fours, and fives. Give each group paper with a chart for writing their ideas. (The paper can be divided into boxes as shown below.)

Things that come in:

Threes
sides of a triangle
colors of the US flag / Fours
legs on a desk
a dog’s legs / Fives
fingers on one hand
sides of a pentagon

Ask each group to read items from their charts, then have the other students guess which number group they belong in. After all groups have reported, display the charts throughout the room. Then ask the students to think about combining equal groups: If one triangle has 3 sides, how many sides will 2 triangles have? Make a classroom T-chart (similar to the one shown) to list the equal groups of triangle sides.

Triangles Sides

1  3

2  6

3  9

As you write their responses in the T-chart, ask the students to explain the meaning of “equal groups” and why we use equal groups when we multiply. Then ask the class if they can show equal groups by drawing a picture using one of the items from their chart. (For example, a child drawing 3 dogs could say that 3 groups of 4 legs equals 12 legs.) As the students finish their drawing, ask them to explain their equal groups to the class.

While they are working, use the chalkboard or overhead projector to draw an array using dots, Xs, or counters to represent a multiplication fact, such as 3x5=15. Use the counters to depict 3 rows with 5 in each row. Then ask the children to identify the corresponding math fact. Explain that an “array” is a picture of equal groups. An array shows a group of objects placed in rows and columns, with each row and column having the same number of objects.

Independent practice:

Give the students several “mental math” multiplication problems:

I have 4 boxes of crayons with 8 crayons in each box. How many crayons in all?

I have 5 rows of chairs with 3 chairs in each row. How many chairs in all?

As the children solve the problems, ask them to explain their solutions with the class.

Then tell the class that they will write their own “real life” multiplication story problem. If needed, provide an example such as, “At my house, I have 2 tables that can seat 5 children. How many children can I invite to my birthday party?”

Each story must end with a question and must be solved by multiplication. They can draw arrays, a picture, or use counters to find the answer, and they may use a calculator to check their work. Each story should also include a number sentence with the answer. Students can write their stories on the Everyday Math number story worksheet, a teacher-made worksheet, or lined drawing paper. Assist students as needed as some may use addition instead of multiplication in their story.

Summarize the Lesson:

As students finish their stories, ask for volunteers to read them to the class. Ask students to identify the factors and product in each number sentence. Students should also be able to explain their solution—did they use counters, draw an array or a picture to arrive at their answer? Display their worksheets where they can be viewed by the class.

Reflections: Ask the students why multiplication is defined as repeated addition. Can they explain why multiplication uses equal groups of numbers? Why and when should you multiply? Why can drawing an array help solve their multiplication problem? How can multiplication be used to solve a “real life” problem?

Extend the lesson: After the students have completed their real life stories and number sentences, they can type their stories onto a computer word processing program, such as Microsoft Word or CompassLearning’s Student Writing Center. These stories can be illustrated using clip art pictures or photos, then printed and bound together to make a class book on multiplication. If a digital camera is available, students can use real objects (fruit, toys, coins, etc.) as the illustrations. Teachers may also help the class create a Powerpoint slide show by allowing each child to design a slide of their story. Once the slide show is completed, it can be used as a learning station to help those children having difficulty in understanding these concepts.

Materials:

Chalkboard or white board

Chalk or dry erase markers

Overhead projector

Calculators

Computers

Digital camera (optional)

Counters (as needed)

Vocabulary cards (teacher made)

Pencils, crayons, colored pencils

Drawing paper, plain and lined

12x18’ paper with chart already drawn, one for each group (small group activity)

My Number Story worksheet (see attachment)

A Number Story Worksheet (Everyday Mathematics Math Masters 3rd grade, p. 23, by the Wright Group, McGraw Hill Co. ISBN 0-07-584489-3)

Duration: 90 minutes

Teacher Notes:

Differentiated instruction: The teacher should consider how to group the students before the math lesson—to be grouped according to math ability levels or according to who can work well together. Students having difficulty may need a partner or “math buddy” instead of working in a group. The small group activity and independent activities can be modified to accommodate the abilities of the class.

Multiplication can be introduced as repeated addition and it is possible that students would solve their number story by addition. Students should realize that addition combines any numbers to arrive at a sum, but that multiplication uses equal groups of numbers. By using counters or drawing an array as they write their story, they can visualize the equal groups used in multiplication. Drawing arrays will help students who have not learned the multiplication facts to arrive at a solution to their story.

While students are working, the teacher should circulate around the room and ask students to explain their ideas for their number story. Listening to their explanations will give the teacher insight as to who needs extra help to complete the assignment correctly. The teacher can ask students who understand and finish quickly to be a math buddy to others having difficulty.

Literature can also be used to introduce multiplication, such as:

Math=Fun Multiplication by Jerry Pallotta; Scholastic Books. ISBN 0-545-00686-4

Amanda Bean’s Amazing Dream by Cindy Neuschwander; Scholastic Books.

ISBN 0-590-30013-X

Each Orange Had Eight Slices by Paul Giganti; HarperCollins.

This lesson was adapted from:

Everyday Mathematics, Third grade teachers manual, chapter 4, lessons 4.1 and 4.2. About Teaching Mathematics A K-8 Resource by Marilyn Burns, Math Solutions, Sausalito CA. ISBN-13:978-0-941355-76-6.

Investigations, Third grade teachers manual.