Conclusion
Students’ use of relational thinking to solve number sentences is evident in all three countries by the end
of elementary school. The extent of its acquisition varies between countries and between schools. Even
where it appears to be strong, there are still many students who seem unable to use it. Those who were
consistent relational thinkers on number sentences were more likely to deal successfully with a sentence
involving literal symbols and number terms than those who showed only arithmetical thinking on the
number sentences. In all the three countries, particularly in Years 5 and 6, the majority of this latter
group were unable to deal successfully with the sentence involving literal symbols. This group should be
a special concern for teachers. They may obtain perfectly correct answers to number questions through
careful use of computational based approaches, but these approaches are clearly deficient when
students are confronted with questions using literal symbols where computation will not work. Their inability to use relational thinking means that they are not well prepared to deal with the kind of thinking
– in particular, those involving equivalence and compensation – that they will need in high school
algebra. More importantly, one should ask how much better their understanding of number and
arithmetical operations might have been in elementary school if they had been introduced to and were
able to use relational strategies to solve number sentences.