thinking about decimal fractions in grades 5&6

Posted on: October 22nd, 2014 by jnovakowski

I have spent two Thursday mornings in Gillian Ewart’s grades 5 & 6 class working with the students as they learn about decimal numbers (tenths, hundredths, thousandths) and how to represent them. Students at this grade level need a strong understanding of tenths and hundredths and then should be able to generalize this understanding to thousandths, ten thousandths, etc. Taking the time to work with concrete materials and visual tools to represent these numbers helps to develop strong conceptual understanding and sense about these numbers that will support students when they begin to apply operations (adding, subtracting, multiplying and dividing) to these numbers.

The iPad app, Skitch, was introduced as a way for students to capture representations of decimal numbers. The students took photographs of hundred grids in the classroom and then used the drawing and text tools within the app. The students saved their images to the iPad’s photo album.

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The students were then introduced to the screencasting app, ShowMe, and students were asked to show what they knew about decimal fractions/numbers by using the images they created in Skitch and then annotating the images further as they narrated their screencasts. Gillian quickly set up a class account on showme.com so the students could log in and save their screencasts to a shared site.

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An example of one of the students first tries at a screencast is posted below:

http://www.showme.com/sh/?h=QDS4HHU

A mathematics-based app that students used to start up their mathematical thinking at the beginning of our second session was Math Tappers: Numberline (an iPhone app). Students chose a range of numbers they felt comfortable working with and a type of numberline (different types of reference points) and then had to place a decimal number where they thought it should go. The students receive feedback as they play. The whole series of Math Tappers apps is excellent and they were developed by University of Victoria professors so they are particularly well suited to our curriculum.

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Next, we introduced the app Number Pieces. The students had been working on representing decimal numbers using base ten blocks and this app has students work with base ten blocks as a virtual manipulative and label and annotate their representations. The students then either used the Number Pieces app or a photo of a concrete representation with base ten blocks to import an image into ShowMe. The students then created a short screencast (we gave them an upper limit of one minute this time) to share their understanding of representing decimal numbers.

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By doing some oral rehearsal before recording, the students are getting more comfortable in communicating their mathematical understanding. The classroom teacher, Gillian Ewart has commented on the insights she gets into her students’ understanding and misconceptions as she listens to and views the screencasts which provide valuable information to plan what comes next in planning her instruction.

~Janice

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