I recently leafed through "Mathematics for Engineers"[0], originally from 1926, which begins with many such methods for making arithmetic easier. Though maybe n

I recently leafed through "Mathematics for Engineers"[0], originally from 1926, which begins with many such methods for making arithmetic easier. Though maybe not always more space efficient. Luckily I got to use a calculator for school. [0]https://archive.org/details/dli.ernet.11725/page/n9/mode/1up https://archive.org/details/dli.ernet.11725/page/n9/mode/1up