This study investigated effective teaching strategies for enhancing mathematical fundamentals in Key Stage 1, specifically in Kindergarten and Grade 1, under the newly implemented MATATAG Curriculum. Anchored on the principle that early numeracy forms the foundation for future academic success. The research addressed the gap in instructional practices within the context of this new curriculum. The significance of the study evaluating how current approaches and pedagogical innovations can enhance young learners' mathematical fundamental skills. This study employed a descriptive-survey research design; quantitative data were collected from Kindergarten and Grade 1 teachers in the districts of Catanauan, Mulanay, and San Narciso, Quezon. It focused on evaluating teaching strategies such as differentiated instruction, technology integration, experiential learning, and collaborative learning, assessing the effectiveness in developing numeracy skills of the pupils. The findings of the study indicated that these strategies positively influenced pupils' engagement and learning outcomes, highlighting the importance of an interactive and hands-on teaching-learning process. Based on these findings, the study developed instructional materials, such as a workbook, to support children in developing mathematical fundamentals. It contains a variety of exercises and activities focused on building skills and mathematical concepts. This study intended to support educators in enhancing teaching methods and improving learning outcomes aligned with the MATATAG Curriculum.