Objective: Students will draw pictures and write related number sentences to solve problems
Standards:
CCSS.MATH.CONTENT.4.OA.A.2: Multiply or divide to solve word problems involving multiplicative comparison, e.g., by using drawings and equations with a symbol for the unknown number to represent the problem, distinguishing multiplicative comparison from additive comparison.
Materials:
· Whiteboards, markers, erasers
· Pencil
· Piece of paper
Lesson Progression:
· Introduction:
o Purpose: “You have used bar diagrams to solve some problems. Today, you will use bar diagrams to write division equations to solve problems.”
o Connect: “When would you pay more, if you were one of 6 friends equally sharing the cost or if you were one of 5 friends sharing the same cost?”
§ Have students share their thinking with explanation.
· Model:
o “Lets look at a problem together: A present for Joan costs $30. How much less will each friend pay if 6 fiends share the cost equally than if 5 friends share the cost?”
o “Now I have to ask myself what do I know? Well, the cost of the present is $30, and either 5 or 6 friends are sharing the total. What is the question asking me to find? The difference between a 6-share and a 5-share. How many bar diagrams do I need? Two, one to show the 6-share, and one to show the 5-share.” Draw two bar diagrams on the board and ask students to tell you how to label each part. “How do you know what operation is needed to solve this problem? Well, since they ask for $30 to be shared equally, I know this means division. So now that I have split up and labeled my bar diagrams, what operation will I use to answer the question the problem is asking (what is the difference between 5-share and 6-share)?” Have students respond. “So I subtract $6 - $5, and get my answer of a $1 difference between a 6-share and a 5-share.”
· Practice:
o “On your white boards, I would like you to solve this problem using the bar diagrams method: A box contains 48 crayons. How many more crayons would each person get if 4 people shared equally than if 8 people shared? Remember to draw a picture and show your work for the answer.”
§ “When you have your answer put a thumbs up and I will check your answer.”
§ Have one student share with the class.
· Extend:
o “I would now like you to find a partner and have one piece of paper per group.”
o “Working together, I would like you to write a problem that can be solved using the bar graph diagrams and division. When you are done put a thumbs up.”
§ Give students a few minutes to write a problem.
o “I now want everyone to stand up and get in a circle around the carpet next to your partner.”
o Once everyone is ready: “Now, I would like you to crumple the paper into a ball. Everyone throw their ball in the middle of the circle. Now when I say go, I would like you and your partner to choose one ball, that is not your own, from the middle of the circle and sit down together to solve the problem using a bar diagram. When you are finished, write your names on the paper you solved, crumple them back up, hold on to the ball, and stand in a circle again.”
o Once everyone is ready: “I would like us all to throw our balls back in the middle. When I say go, I would like you and your partner to choose a different ball from the middle and sit down together. Read the problem and the answer and write down if you agree or disagree with their answer and why. When you are finished you can hand them to me and work on your menu.”
Assessment:
· Students will be assessed throughout the lesson:
o Answer on white board during practice
o Writing a word problem with partner
o Answering a word problem with partner
o Responding to a word problem and answer with partner
Standards:
CCSS.MATH.CONTENT.4.OA.A.2: Multiply or divide to solve word problems involving multiplicative comparison, e.g., by using drawings and equations with a symbol for the unknown number to represent the problem, distinguishing multiplicative comparison from additive comparison.
Materials:
· Whiteboards, markers, erasers
· Pencil
· Piece of paper
Lesson Progression:
· Introduction:
o Purpose: “You have used bar diagrams to solve some problems. Today, you will use bar diagrams to write division equations to solve problems.”
o Connect: “When would you pay more, if you were one of 6 friends equally sharing the cost or if you were one of 5 friends sharing the same cost?”
§ Have students share their thinking with explanation.
· Model:
o “Lets look at a problem together: A present for Joan costs $30. How much less will each friend pay if 6 fiends share the cost equally than if 5 friends share the cost?”
o “Now I have to ask myself what do I know? Well, the cost of the present is $30, and either 5 or 6 friends are sharing the total. What is the question asking me to find? The difference between a 6-share and a 5-share. How many bar diagrams do I need? Two, one to show the 6-share, and one to show the 5-share.” Draw two bar diagrams on the board and ask students to tell you how to label each part. “How do you know what operation is needed to solve this problem? Well, since they ask for $30 to be shared equally, I know this means division. So now that I have split up and labeled my bar diagrams, what operation will I use to answer the question the problem is asking (what is the difference between 5-share and 6-share)?” Have students respond. “So I subtract $6 - $5, and get my answer of a $1 difference between a 6-share and a 5-share.”
· Practice:
o “On your white boards, I would like you to solve this problem using the bar diagrams method: A box contains 48 crayons. How many more crayons would each person get if 4 people shared equally than if 8 people shared? Remember to draw a picture and show your work for the answer.”
§ “When you have your answer put a thumbs up and I will check your answer.”
§ Have one student share with the class.
· Extend:
o “I would now like you to find a partner and have one piece of paper per group.”
o “Working together, I would like you to write a problem that can be solved using the bar graph diagrams and division. When you are done put a thumbs up.”
§ Give students a few minutes to write a problem.
o “I now want everyone to stand up and get in a circle around the carpet next to your partner.”
o Once everyone is ready: “Now, I would like you to crumple the paper into a ball. Everyone throw their ball in the middle of the circle. Now when I say go, I would like you and your partner to choose one ball, that is not your own, from the middle of the circle and sit down together to solve the problem using a bar diagram. When you are finished, write your names on the paper you solved, crumple them back up, hold on to the ball, and stand in a circle again.”
o Once everyone is ready: “I would like us all to throw our balls back in the middle. When I say go, I would like you and your partner to choose a different ball from the middle and sit down together. Read the problem and the answer and write down if you agree or disagree with their answer and why. When you are finished you can hand them to me and work on your menu.”
Assessment:
· Students will be assessed throughout the lesson:
o Answer on white board during practice
o Writing a word problem with partner
o Answering a word problem with partner
o Responding to a word problem and answer with partner