Linear measurement

We are beginning to explore linear measurement:

Today’s problem (Dec 16th):

We activated our thinking with a discussion about the categories of things we measure:

Then we focused on units of measurement, and we made a few connections:

Then we asked today’s question:

Some students solved the problem using repetitive addition:

Some students combines two groups of 60 (to make 120) to make the repetitive addition easier:

Some students used two groups of ten 60’s (600) and a group of 8 60’s (ten 60’s subtract two 60’s or 600 – 120 = 480):

But we focused in on some different answers.  Here the answers were given in both cm and m:

Consolidation: We discussed the idea that units of measurement reflect what is being measured.  We would not measure a hallway in cm, we would use m.  So we talked about how you convert units from one to another.  In this case, how do we convert cm to m and m to cm.  The students had some great observations:

For homework they were given a practice sheet:

Measurement practise sheet conversion of cm and m

Today’s problem (Dec 19):

We activated our brains by converting some measurements from m to cm and from cm to m:

Then we looked at today’s question.  We talked about what information we needed to know (and what information was not necessary):

Although the question was answered in a number of different ways, our focus was not on the solution, but rather on the conversion of cm to m.

Some groups broke down the answer into hundreds (600 cm = 6 m, and the remaining 75 cm come after the decimal point):

Some students simply moved the decimal point 2 spots to the left (divide by 100):

Some students converted the number being added/multiplied (45cm) to m (o.45m) before they started their work, to arrive at an answer in m:

Consolidation: As a group we reviewed strategies to convert cm to m and m to cm.

Today’s problem (a couple of days ago):

To activate our thinking we looked at cm and mm:

We measured some lines:

We reviewed conversions of units:

Then we asked our question:

Students’ explanations focused on how they converted cm to mm or mm to cm:

Consolidation: We had a discussion strategies students used to convert units of measurements.

Today’s problem (Dec 22):

To activate our thinking we looked at how many m are in a km:

Today’s question – as a group we discussed what information was needed to answer the question:

Some students used addition to solve the problem:

Some students used subtraction to solve the problem:

Some students used multiplication to solve the problem:

Some groups were very efficient:

One group used division to solve the problem:

Consolidation:  What we noticed with ALL the solutions was that the problem could not be solved until the two measurements (50m and 1.5km were converted into the same units – either 50m and 1500m or 1.5km and 0.050km.  So we came up with a rule of sorts:




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