Students with emotional and behavioral disorders (E/BD) display severe social and academic deficits that can adversely affect their academic performance in mathematics and result in higher rates of failure throughout their schooling compared to other students with disabilities (U.S. Department of Education, 2005; Webber & Plotts, 2008). Furthermore, students with E/BD are at a greater risk of being served in more exclusionary and restrictive settings compared to their peers as a result of their poor social skills and chronic disruptive behaviors (Gagnon & Leone, 2005; Furney, Hasazi, Clark-Keefe, & Hartnett, 2003; U.S. Department of Education, 2005; Whorton, Siders, Fowler, & Naylor, 2000). This is of great concern as students with E/BD often receive lower grades, fail more classes, have higher drop-out rates, have fewer employment opportunities, and have increased involvement in the legal system (Bullock & Gable, 2006; Cullinan & Sabornie, 2004; Jolivette, Stichter, Nelson, Scott, & Liaupsin, 2000; Kauffman, 2001). The purpose of this study was to analyze the effect of the equal additions algorithm on subtraction with regrouping on the subtraction performance of fourth-grade students with E/BD and mathematics difficulties. The equal additions algorithm was taught using a direct instruction technique. This study investigated 3 participants at the fourth grade level in a residential treatment facility which serves students with E/BD. A multiprobe multiple baseline across participants design was used for this study. Assessments used for this study included (a) "Woodcock Johnson III" ("WJIII"), (b) the "ENRIGHT", (c) a student questionnaire, (d) baseline probes, and (e) an error analysis student profile. Data was analyzed by visual analysis. The results suggest that when the equal additions algorithm was systematically implemented students were able to successfully complete subtraction with regrouping problems and errors dramatically decreased. Limitations and future for research directions are discussed. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]