Word Problem Language and Conversion

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SWBAT recognize when it is necessary to convert units in order to solve word problems.

Big Idea

After examining word problems using meters, grams and liters, students collaboratively practice solving sample word problems and defend their answers.

Warm up: Spiraling around back to division.

10 minutes

Practicing Division Skills

In order to keep standard 4.NBT.B.6 alive, I decided to spiral around in a review for a warm up today. I got out the "24" cards and gave every student a level 1 ( one dot) card. They would use the 4 numbers to create a 4 digit dividend and choose a  divisor from those numbers that would give them the least quotient.

For example: A student draws a card that has 4,5,7,8 on it. The object of the game to arrive at the smallest quotient, so it was my hope they would manipulate the numbers so they create the smallest four digit dividend and divide it by the largest number on the card i.e. 4,578 ÷ 8 . This helps student think about values and how smallest quotients can be produced.

This little warm up task helps them review division. Secondly, it also exercises number sense. We began our task and everyone was engaged immediately. I let them finish in ten minutes and told them to multiply to check their work. Finding a mistake. A student realizes that he has copied numbers incorrectly.

It's called spiraling.. We talked about aha moments that proved that spiraling is a good way to keep things fresh in our minds. I explained that we need to drill some old concepts during warm ups so that they could remember things we learned in the past and maintain their mastery of standards.

Core lesson: seeking out the language and converting in word problems.

20 minutes

Word Problems & Conversion pdf.

Prior to teaching this lesson, each student should have a paper copy of p. 7 of the SB file. I simply copied the page and made a classroom set from the PDF. For students who need the SB file to look at during instruction, I copied the whole file.  It keeps them on task and gives me something to point to on their desk to draw their attention back during whole class instruction.

 Using the SB, I opened the lesson with an example of a conversion word problem. I wanted students to read the problem silently first.  I led the discussion using a few questions from the second page about what strategies we would use to solve the problem.

As we worked through the word problems, students were able to ask questions about problem solving. I used explicit instruction showing them that it was important to form the situation equation. I told them to think about what was going on in the problem and create an equation using the units given. Then, move to creating the solution equation by converting to the units needed to solve the problem. I showed them how to convert, using a T chart. This satisfies the section of the standard that requires students to convert in a two column chart.

When we got to the 5th page of the SB file, students were reminded to use their strategies, create situation equations and solution equations as they solved the problems together. I asked  a student to come to the SB and show how she converted. She was confused about the use of the t chart and had the concept wrong. T chart conversion We worked together to get it corrected so others weren't confused.T chart Misunderstanding Corrected. For some reason, she thought she had to convert both numbers. I think this is where the "how" gets in the way of the "why" with students. She was not thinking about why she was converting, she just knew she needed to. We solved the problem and finished it up. Students copied it step by step in their notebooks. I insisted on equations with variables and proper labels.

We worked on the problem on page 6 together. This one was challenging because we needed to convert kg to g. Students set up their KWS chart and a T chart in their notebooks. I roved the classroom checking progress and fluency.

Partnered Practice

30 minutes

I had planned to assign p 7 as independent practice, but decided that partner work would better support their mastery of the standard. While they had mastered conversions in a two column chart, the word problems presented a greater challenge.  I partnered advanced ability with struggling students in hope that this would help students gain confidence in problem solving.

 They set up their KWS charts by dissecting the problem and then classifying it into the sections of K ( What do I know? What do I want to know? How do I solve the problem? See student samples for an example.) I roved the classroom, checking on how they were solving. The situation equations were difficult for them to write because they kept wanting to just convert and solve.

I had to continually guide them to write it out as it was stated in the problem.  I changed the "S" to "Situation" in their KWS charts. This corrected the neglect of writing just the solution. It kept them from mistakenly solving before they converted.

Students had solved the problems in about thirty minutes. Some students needed to solve one more, but I needed to stop the lesson. They took it home for homework.