Although slide rules existed before Mannheim's time, invented by Oughtred and Gunter and others, it was Mannheim who standardised the modern version of the slide rule which was in common use until pocket calculators took over a few years ago.
Kahit na slide patakaran nabuhay bago Mannheim ng oras, sa pamamagitan ng imbento Oughtred at Gunter at iba pa, ito ay Mannheim na standardised ang modernong bersyon ng slide na batas na kung saan ay sa mga karaniwang gamitin ang hanggang sa bulsa calculators kinuha sa loob ng isang ilang taon na ang nakalilipas.