It's difficult to imagine a time before mass-produced electronic calculators. Not counting pen and paper, slide rules[front][back] and log tables were the only way to perform calculations with far magnitude numbers and the elementary transcendental functions (sine, cosine, logarithm, etc). Slide rules were quite fast but they were limited to around 3 digits of accuracy. Four figure printed tables were quite common and (obviously) provided around 4 digits of accuracy, but a bit of practise and skill was required to look up the tables and tally the intermediate results with pen and paper. Training with log tables was a standard part of basic mathematics lessons for high school students in the early 1970s. Five figure log tables were more expensive and more difficult to find in retail stores, so a small bit of prestige was associated with owning one.