This study explored the number sense of 47 final year primary school pre-service teachers in Namibia
and was motivated by the poor performance of Namibian primary school learners in both national and
international standardised assessment tests. The literature review revealed that learner performance is
linked to teacher subject knowledge (Ball, 1990, Ma, 1999) and that teachers’ confidence in doing and
teaching mathematics influences the way they teach and their willingness to learn mathematics (Ball,
1990; Graven 2004). Number sense studies of pre-service teachers (Kaminski, 1997; Tsao, 2004;
Veloo, 2010; Yang, Reys & Reys, 2009) have indicated that the development of number sense should
be a focus of primary pre-service teacher education.
The data in this mixed method research design were obtained from a Number Sense Questionnaire, a
Written Computations Questionnaire and a Mental Calculations Questionnaire. These questionnaires
were adapted from instruments developed by Professor Der-Ching Yang for 6th and 8th grade learners
in Taiwan. Teacher confidence was measured by the McAnallen Confidence in Mathematics and
Mathematics Teaching Survey. Six randomly selected pre-service teachers were interviewed to
determine their use of number-sensible strategies.
The correlation analysis shows a strong relationship between number sense and mental calculations;
between number sense and confidence in both the ability to do and the ability to teach mathematics and
between mental and written calculations.
The overall results of this study reveal that the final year primary pre-service teachers demonstrate
limited number sense and possess very few of the indicators of number sense that were described by
Kalchman, Moss and Case (2001). The findings expose a lack of conceptual understanding of the
domain numbers and operations, particularly in the domain of rational numbers and the operations of
multiplication and division. The pre-service teachers have little or no access to a variety of flexible
number-sensible strategies to solve problems and calculate mentally. They lack the fluency in basic
facts and procedures to perform written calculations efficiently and correctly. Unexpectedly, the
analysis of the confidence survey shows that they are confident in both their ability to do mathematics
and their ability to teach mathematics.
It is recommended that mental calculations and computational estimation should become a focus of
primary school mathematics education. Institutions responsible for teacher training should develop the
number sense of pre-service teachers and research effective and long-term professional development
programmes. The confidence and willingness of the teachers to learn can be used as an important
resource.