Past studies revealed that the integration of ethnomathematics approaches is of great importance in the teaching and learning of mathematics as it is believed to improve learners' understanding and achievement in mathematics. Cognisant of the benefits of using ethnomathematics approaches in teaching and learning mathematics, the Zimbabwean school syllabus recommends the adoption and integration of ethnomathematics approaches to improve the learners' performance. The purpose of this mixed-method study was to determine the comparative effectiveness of ethnomathematics approaches and the traditional lecture approaches as well as teachers' views on the use of ethnomathematics approaches. The study sample comprised 90 learners and two teachers from one secondary school in Bindura district in Zimbabwe. Two instruments, a test and interviews were used for data collection. The participating teachers taught the concepts of consumer arithmetic for four weeks. Findings of the study showed that learners taught using an ethnomathematics approach achieved significantly higher in the test than those taught consumer arithmetic using the traditional approach. The study revealed that teachers appreciated the use of ethnomathematics approaches in the teaching of consumer arithmetic as their learners were motivated, actively involved and interested in learning the concepts. It was also reported that ethnomathematics approaches improve learners' understanding and retention of arithmetic concepts. The study, therefore, recommended training of the teachers on the use of the ethnomathematics approach in the teaching and learning of consumer arithmetic.