4: Arithmetic and Mental Mathematics
( \newcommand{\kernel}{\mathrm{null}\,}\)
Thumbnail: Animated example of multi-digit long division. (CC BY-SA 3.0; Xanthoxyl via Wikipedia)
( \newcommand{\kernel}{\mathrm{null}\,}\)
Thumbnail: Animated example of multi-digit long division. (CC BY-SA 3.0; Xanthoxyl via Wikipedia)