source: Before the advent of the pocket calculator, it was the most commonly used calculation tool in science and engineering.
target: It was the most commonly used calculation tool before the invention of the pocket calculator.
references: It was the most commonly used calculation tool before the invention of the pocket calculator. Before the pocket calculator was invented it was common as an science and engineering tool. Before the pocket calculator was invented, it was the most popular calculation tool in science and engineering. The pocket calculator replaced its use in science and engineering. Before the pocket calculator was invented it was the most used calculation tool. Before the invention of the pocket calculator, it was the most often used calculation tool for science and engineering. It was the most commonly used calculation tool before the pocket calculator. It was the most common tool before the calculator. Before the invention of the pocket calculator, it was the most common counting tool in science and engineering. It was the most used calculation tool in science and engineering before the pocket calculator came out.