Objective: When students learn or solve problems, attentional resources are depleted; rest breaks may restore cognitive functioning in support of learning. Research framed by attention restoration theory holds that exposure to natural environments may be another means to restore attentional resources. The study investigated the effects of alternative rest break formats on learning a challenging mental mathematics strategy. Method: Students first completed a series of timed arithmetic tests expected to deplete attentional resources. Students in the control condition proceeded directly onto a mental mathematics lesson, while students in the unstructured rest and nature-based rest conditions took a 5-min break before the lesson. All students then completed a self-reported questionnaire on directed attention levels during the lesson, then completed a problem-solving post-test. Results: The unstructured rest condition reported higher levels of directed attention during the lesson than the control condition; no other comparisons were statistically significant. The unstructured rest condition solved more post-test problems than the control condition, and the nature-based rest condition also solved more problems than the control condition. The post-test score difference between the two rest conditions was not statistically significant. Conclusions: The study provided clearer evidence for the general benefits of rest than for the additional benefits of nature-based rest.