ABSTRACT
Three textbooks from Brazil and three textbooks from the United States were analysed with a focus on similarity and context-based tasks. Students’ opportunities to learn similarity were examined by considering whether students were provided context-based tasks of high cognitive demand and whether those tasks included missing or superfluous information. Although books in the United States included more tasks, the proportion of tasks focused on similarity were about the same. Context-based similarity tasks accounted for 9%–29% of the similarity tasks, and many of these contextual tasks were of low cognitive demand. In addition, the types of contexts that were included in the textbooks were critiqued and examples provided.
Acknowledgments
This research has been financed by FAPESP (Process 2013/22975-3) and by CAPES (Process BEX 0612/15-4).
Disclosure statement
No potential conflict of interest was reported by the authors.
Notes
1. Programa Nacional do Livro Didático (PNLD).
2. When two parallel lines are cut by two transversals, measures of segments of the first transversal are proportional to the measures of the corresponding segments determined on the second transversal ([Citation28], p. 92).
3. The tasks from Brazilian textbooks were translated to English.
4. From Integrated Mathematics Course 2, Teacher Edition. Copyright © 2012 by McGraw-Hill Education. All rights reserved. Reprinted by permission of McGraw-Hill Education.
5. From INTEGRATED MATHEMATICS, Teacher Edition with Solutions Key. Copyright © 2015 by Houghton Mifflin Harcourt Publishing Company. All rights reserved. Reprinted by permission of Houghton Mifflin Harcourt Publishing Company.