Summer Ventures in Science and Mathematics is a four-week summer enrichment program where high school students study a variety of STEM topics. This article explores how participation in the Mathematical Evolution course affected students' skills in research, communication, and scientific reasoning and changes in self-efficacy towards STEM. Data was gathered using the Test of Scientific Literacy Skills (TOSLS), S-STEM survey, as well as examining student research papers, presentation posters, oral presentations, and presentation slides. Evaluation of student research papers indicated that students were able to identify and state a research problem, cite sources of information, and write the final report with support from mentors. The TOSLS indicated that students understand the scientific process and apply mathematical principles when given data, though they lack the ability to interpret data. Analysis of a two-tailed T-test of the S-STEM survey revealed that students' self-efficacy remained largely unchanged, but four items showed a statistically significant change pre- and post-program. This study indicates students improved their skills in research, communication, and scientific reasoning and self-efficacy by participating in an intensive summer mathematics program.