The issue of connecting school mathematics contents and instruction to the learners’rnsocio-cultural and real life context is increasingly attracting the attention ofrneducational practitioners including teachers and students themselves. The overall aimrnof the current study was to investigate the everyday mathematical practice and thernissue of connecting in-and out-of-school mathematical practices. Guided by the desirernof adding empirical knowledge, the present study examined this issue in one ofrnEthiopia’s ethnic groups, the Khimra people. The study was conducted in eightrnworkplaces, two games, and two schools selected purposively. Twenty fiverninformants were purposively selected from these workplaces, games, and schools. Thernstudy used a qualitative multiple (embedded) case study design to address the problemrnof connecting workplace and school mathematical practices that the current literaturernin Ethiopia does not adequately cover. Data obtained from interviews, field notes,rnclassroom and workplace observations, and documents were analyzed and discussedrnusing Saxe’s (1991) analytical framework. The results demonstrated that peoplernengaged in workplaces outside school use mathematical ideas, concepts andrnprocedures in their real life activities. Interviews with and observations of participantsrnin workplaces showed that the nature and activity structure of a given work leads to arnparticular mathematical practice and this mathematical activity helps the successfulrnaccomplishment of the work. Moreover, the findings showed that in- and out-ofschoolrnmathematical practices can interplay to enhance the process and means ofrnachieving the goals of one another. However, this potential interplay is not researchedrnand recognized by educational practitioners such as teachers. Therefore, it is possiblernto claim that learning and understanding of mathematical concepts by students can bernenhanced by the positive interaction between the in- and out-of-school mathematicalrnpractices. The implication of these findings is that understanding the out-of-schoolrnmathematical practices and their roles in improving school mathematics instruction isrnuseful to inform larger policy goals about the importance of contextualizingrnmathematics curriculum and instruction. The challenges mentioned by teacherrnparticipants also imply that teacher training colleges need to give attention to thisrnissue to inform their trainees and future teachers about the importance ofrncontextualizing mathematics instruction