Complex sentence: He took a job as a farmhand on Vansta, a property in Södertörn, Stockholm, he quickly rose to the position of supervisor, being responsible for supervision and accounting, something suited for his affinity for mathematics.
Split into simpler sentences: He took a job as a farmhand on Vansta, a property in Södertörn, Stockholm. He quickly rose to the position of supervisor, being responsible for supervision and accounting, for which he was well suited by his affinity for mathematics.