This study compared number sense instruction in three first-grade traditional mathematics textbooks and one reform-based textbook (Everyday Mathematics [EM]). Textbooks were evaluated with regard to their adherence to principles of effective instruction (e.g., big ideas, conspicuous instruction). The results indicated that traditional textbooks included more opportunities for number relationship tasks than did EM; in contrast, EM emphasized more real-world connections than did traditional textbooks. However, EM did better than traditional textbooks in (a) promoting relational understanding and (b) integrating spatial relationship tasks with other more complex skills. Whereas instruction was more direct and explicit and feedback was more common in traditional textbooks than it was in EM, there were differences among traditional textbooks with respect to these two criteria. Although EM excelled in scaffolding instruction by devoting more lessons to concrete and semiconcrete activities, traditional textbooks provided more opportunities for engaging in all three representations. However, EM emphasized (a) a variety of models to develop number sense concepts, (b) a concrete, or semiconcrete, to symbolic representational sequence, and (c) hands-on activities using real-world objects to enhance learner engagement. Finally, even though traditional textbooks excelled over EM in providing more opportunities to practice number sense skills, this finding may be an artifact of the worksheet format employed in traditional textbooks. At the same time, adequate distribution of review in subsequent lessons was evident in EM and in only one of the traditional textbooks. Implications for practice in accessing the general education curriculum for students with learning problems are discussed.