This researcher has been greatly distressed, as fifth graders year after year have disregarded mental math strategies for the standard algorithm. Mathematically proficient students should be flexible, efficient and accurate when solving mental calculations. This researcher set out to find out how fifth graders' mental math practice improved their numeracy. The questions addressed included how students improved in flexibility, accuracy and speed. This should inform the practice of teachers to help better our numeracy of our students. This article contends that Number Talks practiced two days a week, benefits numeracy in 22 fifth graders during a six-week cycle. In this Triangulation Mixed-Methods Design, data was collected that included pretest- posttest same test combined with an interview where the participants explained the strategies they used. The mean showed a greater improvement in the treatment group, however, paired-samples t-tests findings indicated flexibility and accuracy did not show a significant difference, but speed did incur a significant improvement. Additionally, students increased in their confidence when solving mental calculations. Moreover, an additional survey showed greater flexibility in the treatment group at the cycle's end. Number Talks, therefore may increase students' numeracy in the strand of efficiency. Researchers need to further study the degree practice through Number Talks improves numeracy in fifth graders.