3.1 Introducing Multiplication
Unit Goals
- Students represent and solve multiplication problems through the context of picture and bar graphs that represent categorical data.
Section A Goals
- Interpret scaled picture and bar graphs.
- Represent data using scaled picture and bar graphs.
- Solve one- and two-step story problems using addition and subtraction.
Section B Goals
- Represent and solve multiplication problems involving equal groups.
- Understand multiplication in terms of equal groups.
Section C Goals
- Represent and solve multiplication problems involving arrays.
Section A: Interpret and Represent Data on Scaled Graphs
Problem 1
Pre-unit
Practicing Standards: 2.MD.D.10
The table shows how a group of students most enjoy traveling. Use the table to complete the picture graph.
way to travel | number of students |
---|---|
airplane | 4 |
hot air balloon | 7 |
sail boat | 6 |
scooter | 3 |
Solution
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Problem 2
Pre-unit
Practicing Standards: 2.MD.D.10
Use the bar graph to answer the questions.
- How many students recorded their favorite animal?
-
How many fewer students chose hamsters than dogs?
Solution
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Problem 3
Pre-unit
Practicing Standards: 2.MD.D.10
The table shows the favorite summer vacation activity for a group of students.
vacation activities | number of students |
---|---|
family time | 6 |
playing sports | 8 |
sleeping in | 5 |
reading | 3 |
Use the table to complete the bar graph.
Solution
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Problem 4
Pre-unit
Practicing Standards: 2.NBT.B.5
Find each sum or difference. Show your reasoning.
- \(25 + 62\)
- \(37 – 9\)
- \(24 + 47\)
- \(84 – 59\)
Solution
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Problem 5
Pre-unit
Practicing Standards: 2.OA.C.4
How many objects are in each array? Explain or show your reasoning.
Solution
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Problem 6
The graph shows some information about flowers in the garden.
- Write one fact you know based on the data shown in the graph.
- Write 2 questions you could answer about the data in the bar graph.
Solution
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Problem 7
The bar graph shows the numbers of different types of flowers in the garden. Use the graph to answer the questions.
- How many flowers are represented on the graph?
- How many tulips, sunflowers, and daffodils were there altogether?
Solution
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Problem 8
This picture graph records types of balls in the gym. Use the graph to answer the questions.
- How many basketballs are in the gym?
- How many more basketballs are there than footballs?
- Write one other question that you could answer about the balls in the gym using the graph.
Solution
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Problem 9
The table shows the favorite sports of some students. Use it to complete the scaled picture graph.
sport | number |
---|---|
tennis | 6 |
swimming | 6 |
gymnastics | 4 |
soccer | 8 |
Solution
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Problem 10
The table shows the number of different shapes in a pattern block puzzle. Use it to complete the scaled bar graph.
shape | number |
---|---|
triangle | 13 |
trapezoid | 10 |
square | 9 |
hexagon | 15 |
Solution
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Problem 11
The table shows the number of books some students have at home.
Use the information from the table to create a scaled bar graph.
books | number |
---|---|
Elena | 25 |
Andre | 9 |
Tyler | 16 |
Clare | 21 |
Solution
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Problem 12
The graph shows the number of different kinds of nuts in a bowl.
- How many more pistachios are there than walnuts? Explain or show your reasoning.
- How many fewer pecans are there than peanuts? Explain or show your reasoning.
Solution
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Problem 13
The scaled bar graph shows how many students are in each class.
- How many students are in the 4 classes altogether? Explain or show your reasoning.
- How many fewer students are in class 1 than in class 4? Explain or show your reasoning.
Solution
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Problem 14
Exploration
There are 1,000 students at the 4 schools. What is the approximate scale for the bar graph?
Solution
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Problem 15
Exploration
Collect data of interest to you and make a bar graph. You may use the bar graph template if you wish.
Solution
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Section B: From Graphs to Multiplication
Problem 1
There are 6 tennis courts. There are 2 players on each tennis court.
Create a drawing or diagram to represent the tennis players. Then, find out how many players are on the tennis courts. Explain or show your reasoning.
Solution
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Problem 2
The picture graph shows the favorite colors of some students.
Match each diagram or drawing to the number of people who like each color.
Solution
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Problem 3
Create a drawing or diagram to represent the expression \(4 \times 3\).
Solution
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Problem 4
There are 4 stacks of books on the table. Each stack has 5 books. How many books are on the table? Explain or show your reasoning.
Solution
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Problem 5
There are 6 basketball teams in the gym. There are 5 people on each team. How many people are on the basketball teams in the gym?
- Write an equation with a symbol for the unknown to represent the situation.
- Find the number that makes the equation true. Show your reasoning.
Solution
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Problem 6
Write an equation for the situation. Use a ? for the unknown. Find the number that makes the equation true.
There are 4 soccer teams. Each soccer team has 10 players. How many players are there altogether?
Solution
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Problem 7
Solve each problem. Explain or show your reasoning.
- There are 6 flowers. Each flower has 5 petals. How many petals are there?
- There are 50 petals on some flowers. Each flower has 5 petals. How many flowers are there?
Solution
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Problem 8
Exploration
Write an expression for the number of circles in the image. Then, find the number of circles.
Solution
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Problem 9
Exploration
For each image, determine if there is an even or odd number of circles. Explain or show your reasoning.
Solution
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Problem 10
Exploration
Look in your classroom, school, home, or outdoors to find some equal groups of objects.
- Describe the objects.
- Create a drawing to represent the objects.
- Write an equation showing how many objects there are.
Solution
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Section C: Represent Multiplication with Arrays and the Commutative Property
Problem 1
Rearrange the circles to make an array in two different ways.
Solution
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Problem 2
There are 4 rows of water bottles in the box. There are 5 bottles in each row.
Draw an array representing the situation. Then, write a multiplication expression representing the number of water bottles.
Solution
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Problem 3
There are 5 rows of chairs in the room. There are 4 chairs in each row. How many chairs are in the room?
- Write a multiplication equation to represent the situation.
-
Find the value that makes your equation true.
Solution
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Problem 4
- Write a multiplication equation that represents each array.
- How are the arrays the same? How are they different?
Solution
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Problem 5
-
Explain or show 2 different ways that you see equal groups in the array.
-
Arrange the dots in an array in a different way.
Solution
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Problem 6
Exploration
Andre says that there are an odd number of circles in this picture.
Do you agree with Andre? Explain or show your reasoning.
Solution
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Problem 7
Exploration
Find a collection of objects in the classroom or at home that is arranged in an array.
- Describe the objects.
- Create a drawing of the objects.
- Write an equation showing how many objects there are.
Solution
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