Simplify the following text for a Grade 14 native English-speaking person.
Original: Three different factors seem to have influenced him : a dislike of untidiness ; his experience working on logarithmic tables ; and existing work on calculating machines carried out by Wilhelm Schickard , Blaise Pascal , and Gottfried Leibniz .
Simplified: Two different factors seem to have influenced him : his experience working on logarithmic tables and existing work on calculating machines carried out by Blaise Pascal , and Gottfried Leibniz .