Converting Length using Metric System

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The students will be able to convert measurements of length within the Metric System.

Big Idea

Meters are Unhappy!


15 minutes

Today’s lesson will focus on converting lengths within the Metric System.  Students will measure the length and width of the gym in meters and then convert the measurements to centimeters and kilometers.  During the second part of the lesson students will be practicing converting weight amongst all the units of Metric length.  The lesson will end with an exit slip to check for understanding that includes three real-world story problems involving converting length in the Metric system. 

To begin today’s lesson I take students down to the gym and provide them with metersticks.  I have students work in pairs to measure the length and width of the gym.  They record their measurements on a sticky note or index card.  Students are instructed to round their measurements to the nearest meter.  We return to the room to discuss our measurements. 

I write the length and width measurements on the board.  Most measurements are within a meter of each other so we take the most frequent measurement to use for our conversions. 

Okay now let’s convert these measurements from meters into centimeters.  First, let’s write our mnemonic we learned in yesterday’s lesson in abbreviated form. 

I write khdudcm on the board.  Although in yesterday’s lesson we created a foldable for this mnemonic I want students to realize that this information can be recalled easily by writing these seven letters.  I show them how we can easily use these letters to figure out where the decimal is going to move to.  I allow students to have their foldable out to reference for now.

Now that we have our mnemonic written, where is meters?  I don’t see a m for meter.  I know this m stands for milli. 

I guide students a self-discovery that now the letter u becomes meters because our unit is meters.  Students quickly figure out the u is now replaced by meters.  I continue probing them to see if they can discern the centi becomes centimeter.  Since centi is a prefix we need to add it on to a word.

Well, now that we have that figured out, how do we convert from meters to centimeters?  What is going to happen to the number?  Does it get bigger or smaller?  Are we multiplying or dividing when we move to centimeters from meters?  Can you make a connection between how we converted between lengths in the U.S. Customary system?

My goal is that students are able to verbalize the multiplying and dividing by tens when moving from prefix to prefix.   We also convert our meters measurement to kilometers. 


30 minutes

After modeling for the students how to do conversions of our gym measurements I now have students work in pairs to complete a skills sheet for today.  I allow the students about twenty minutes to complete the conversions while I circulate the room and support students. 

At the end of the practice time I call students up to the whiteboard to explain their thinking for solving a specific conversion from the sheet.  While students are presenting their thinking I ensure that students are using the terms appropriate vocabulary associated with the conversion they are completing.    

We then add meters to our graphic organizer under metric system length


15 minutes

To wrap up this lesson I have students complete an exit ticket which includes three story problems I created involving converting length units.  I use this information to guide me in deciding if further clarification is needed in converting length.  I look to see where students struggled to pin point exactly what part of converting is unclear to them.