AUTHOR=Mende Melinda A. , Shaki Samuel , Fischer Martin H. TITLE=Commentary: The mental representation of integers: An abstract-to-concrete shift in the understanding of mathematical concepts JOURNAL=Frontiers in Psychology VOLUME=9 YEAR=2018 URL=https://www.frontiersin.org/journals/psychology/articles/10.3389/fpsyg.2018.00209 DOI=10.3389/fpsyg.2018.00209 ISSN=1664-1078