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Case Studies

collageMany children and adults hold misconceptions about decimal notation. This section presents six case studies of people holding different misconceptions. Each case study contains:
results of the Decimal Comparison Test.
interviews of the person completing four tasks.
a short test to check your understanding of this thinking.
lesson ideas appropriate for a student with this misconception.

Case Study 1: Caitlin
Whole Number Thinking
These learners consider that the digits after the decimal point make another whole number.
Case Study 4: Brad
Column Overflow Thinking
These learners know column names but try to put more than one digit into a column.
Case Study 2: Courtney
Reciprocal Thinking
These learners interpret decimals as fractions.
Case study 5: Tuyet
Reverse Thinking
These learners have not heard the 'th' sound in the column names.

Case Study 3: Ricardo
Denominator Focussed Thinking
These learners know that tenths are larger than hundredths, but think that any number of tenths is larger than any number of hundredths.

Case Study 6: Maria
Money Thinking
These learners make an analogy with dollars and cents.
The case studies are derived from interviews with Australian children in Years 4 to 10 and with adults. They were conducted as part of the research study "Improving learning outcomes in numeracy" (funded by the Australian Research Council with chief investigators Professors Kaye Stacey and Liz Sonenberg) and Vicki Steinle's PhD thesis. The identities of interviewees have been changed. Interviews have been edited, amalgamated and some parts have been 'created', to present the reasoning clearly.

For information about this page, contact: Vicki Steinle
Contact Email Address: v.steinle@unimelb.edu.au
Faculty Homepage: http://www.edfac.unimelb.edu.au/sme/
Last modified: Sun 16 April 2006

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