Purpose.

The article presents a descriptive-comparative analysis of how rational numbers are taught in four mathematics programs developed in Chile from 1974 to 2012, encompassing from third to sixth grade (ages 8-12).

Methods.

The learning objectives were analyzed based on the notion of fractions, decimals, and percentages, following the standards set by the National Council of Teachers of Mathematics (NCTM, 2003). Content analysis was used as the method.

Results.

Most of the notions and understanding the rational number are recurrent aspects across the programs. However, they vary in their flexible use, representations, calculation and solving problems processes.

Discussion.

The observed evolution in the topic is found to be related to social changes and educational policies during the time period.