Students' addition of decimal fractions: the effects of context

Turton, A 2012 , 'Students' addition of decimal fractions: the effects of context', Coursework Master thesis, University of Tasmania.

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Abstract

Queensland and national curriculum documents of recent years suggest that addition and
subtraction of decimal fractions can occur in a money context earlier than they do without a
context. However, there does not appear to be enough research to support the legitimacy of
this approach and the lack of fine detail in the curriculum documents has resulted in a variety
of interpretations taken by textbook writers and presumably teachers.
Some research has shown that the use of contexts to make mathematics more relevant to
students can have unintended results. Among these is the negative impact that using money
problems as exemplars can have on the conceptualisation of decimal fractions. Given this
finding, together with the limited guidance in the relevant curriculum documents and the
variety of presentations by textbook publishers, this study sought data on the following
questions:
1. How does accuracy with addition differ when decimal fractions to hundredths are written
with dollar signs compared to when they are not?
2. How do addition methods differ when decimal fraction problems using hundredths are
contextualised with dollar signs compared to when they are not?
A cross-sectional study was undertaken to provide a snapshot of school students’ ability to
undertake decimal computation addition problems in contextualised and non-context
situations. Students in Years 4 and 5 in Queensland state schools completed one of two test
papers. One paper presented addition problems involving decimal fractions without any
context (e.g., 1.30 + 1.20). The other paper had identical questions but with a dollar sign
included for each decimal fraction ($1.30 +$1.20). Altogether 161 students participated.

The results showed that there was a difference in accuracy in favour of the group working
with non-contextualised decimal fractions. It was also revealed that the group working with
the money context reported answers for particular questions in ways that may indicate
underlying conceptual errors about money or about the relationship between money and
decimal fractions. It was found that the students working without a money context preferred
showing their thinking using a standard written method in greater numbers than did the
students working with the contextualised problems. The latter group, in contrast, had a
greater incidence of writing answers but without recording a method. Although no difference
in accuracy was observed between males and females, some difference in method choice was
recorded.

Item Type: Thesis - Coursework Master Turton, A education, mathematics, addition, context, decimal fraction, primary students Copyright the Author View statistics for this item