This study was performed to test the next matter, the possibility of treating the
intensive quantity as the extension quantity, and the necessity of dividing the instruction
grade of “size per unit quantity” and “speed” in the intensive quantity. Fourth, fifth, and
sixth grade students participated in this study. They had not received formal instruction
on speed. They were asked to solve problems using three terms of proportion about speed
and price per unit, and to answer subjective difficulties about these problems. As a result,
the following five points were clarified: (a) there was no significant difference in the scores
of fifth graders, and sixth graders on any of the problems; (b) the fourth graders’ scores on
the problem were significantly lower than the scores of other grades; (c) the scores on the
first and third terms of proportion were lower than the scores on the second term of
proportion in the fourth grade; (d) in the fifth and sixth grades, there was no significant
difference in the subjective difficulty of the speed problem; and (e) regardless of the
problems, every grade found the first and third terms of proportion difficult. These results
suggest that it is possible to treat the intensive quantity as the extension quantity, and to
teach “speed” like “price per unit” or “density” in instruction on multiplication or division;
this would require instruction in division to be associated with instruction on
multiplication.
View full abstract