Solving problems about bar graph data - math grade 2 - lesson 5

We have been looking at and making bar graphs. Today we are going to look at a new bar graph. Look closely at the graph and think about how it is the same as and different than other bar graphs we have seen.

1.TEACHER DO: Display the large Our Favorite Fruit bar graph.

STUDENTS DO: Discuss with Shoulder Partner the similarities and differences among this graph and other graphs they have worked on.

TEACHER DO: Give 1 to 2 minutes for students to discuss and then use an Attention Getting Signal. Use Calling Sticks to choose 2 or 3 students to share observations.

STUDENTS DO: Selected students share their observations.

2.TEACHER SAY: Thank you for sharing your thinking. I am going to ask a few questions about the data on this graph.

TEACHER DO: Use Calling Sticks to select students to answer questions about the graph (such as the questions below). Ask questions based on the needs of the group.

TEACHER SAY:

• What is the most popular fruit on this graph? How can you tell?

• Which fruit is liked the least? How can you tell?

• Are there any fruits that have equal numbers of people that like them? How can you tell?

STUDENTS DO: Selected students answer the teacher’s questions.

3.TEACHER SAY: Nice job. Now we are going to look a little deeper into this data and do some addition and subtraction to compare the data more. I would like to know how many people liked strawberries and bananas. To figure this out, I have to add together the number of people who like strawberries and the number of people who like bananas. When I add, I am finding a SUM. Repeat the word SUM.

STUDENTS DO: Repeat the word “sum.”

TEACHER SAY: Tell me how many people liked strawberries.

STUDENTS DO: Look at the graph and call out the answer.

TEACHER SAY: Tell me how many students liked bananas best.

STUDENTS DO: Look at the graph and call out the answer.

TEACHER SAY: Great. Now we can add 9 + 7 together to find the sum. Raise your hand when you know the sum of 9 and 7.

STUDENTS DO: Raise hand when they have the answer. Selected students answer the question.

TEACHER DO: Confirm the correct answer or ask other students until the correct answer is provided.

4.TEACHER SAY: Now let’s compare how many more people liked bananas than oranges. We know from the last problem that 7 people liked bananas best. Look at the graph and Whisper into your hands how many people liked oranges.

STUDENTS DO: Whisper “3” into hands.

TEACHER SAY: Yes, 3 people liked oranges best. How many MORE people liked bananas best Give me a Thumbs Up when you have an answer and would like to come up and share with the class how you found the answer.

STUDENTS DO: Think quietly. Give a Thumbs Up when they have an answer. Selected students share their answers and explain their thinking and strategy.

TEACHER SAY: Thank you. Who figured out the answer using a different strategy? Give me a Thumbs Up.

STUDENTS DO: Give a Thumbs Up if they used a different strategy. Selected students share their answers and explain their thinking and strategy.Note to the Teacher: Some students may compare the bars and count the difference between the banana bar and the orange bar. Some students may count up from 3 to 7 to determine the answer. Other students may subtract the lower number (3) from the higher number (7) to solve the problem. All of these methods are appropriate and should be commended. However, since students are expected to subtract to find “how many more,” be sure to model that strategy if no students share it. A procedure is provided below that addresses all of these methods. Skip the strategies the students already shared.

TEACHER SAY: Thank you for sharing your thinking and your strategies. Wonderful work. There is another way to find the answer. When we are trying to find out how many more, we are trying to find out the DIFFERENCE. You say difference.

STUDENTS DO: Repeat “difference.”

TEACHER SAY: When we need to find the difference, we look at both numbers. On this graph, 3 people liked oranges and 7 people liked bananas. I can see from the graph that 4 more boxes are colored in on the banana bar, or column, so the difference is 4. I started at 3 and counted up to 7. I know that 3 plus 4 equals 7, so the difference is 4.

TEACHER DO: Write 3 + 4 = 7 on the board.

TEACHER SAY: I can also start with the larger number and subtract the smaller number to find the difference.

TEACHER DO: Write 7 – 3 = 4 on the board.

4.TEACHER SAY: We can do a lot of different things with data in graphs. We can add two categories together and find the SUM, or we can count up or subtract to find the DIFFERENCE between two categories, or bars. Take out your student book and open it to page Lesson 5: Apply.

STUDENTS DO: Open student book to the page for Lesson 5.

TEACHER SAY: For the rest of the class, you will work with your Shoulder Partner to answer questions about the data. I will read them to you now. Try and answer as many as you can. You can get counters to help you, or you can use any other strategy you have to find the answers.

STUDENTS DO: Work with Shoulder Partner to answer as many questions as they can in the class time left.

TEACHER DO: Walk around the class observing students as they work. Offer help where necessary. Note students who need extra support or may need reteaching later. When class time is coming to an end, use an Attention Getting Signal to bring the group back.

5.TEACHER SAY: Good job today. Put away your pencil and any materials but keep out your student book.

STUDENTS DO: Clean up supplies.