@article{rathgeb-schnierer_green_2019, title={Developing Flexibility in Mental Calculation}, volume={44}, ISSN={2175-6236}, url={https://doi.org/10.1590/2175-623687078}, DOI={10.1590/2175-623687078}, number={2}, journal={Educação & Realidade}, publisher={Universidade Federal do Rio Grande do Sul - Faculdade de Educação}, author={Rathgeb-Schnierer, Elisabeth and Green, Michael G}, year={2019}, pages={e87078} }