The Islamic contributions to science including mathematics was largely derivitive, confined largely to preserving the knowledge of earlier Greek, Roman and Indian writers.
As with every early civilization throughout history the tempraments of the individual rulers determined the tenor of the times.
Some Muslim rulers were relatively enlightened as judged by the standards of their period while others were little more than bloodthirsty savages.
This matters to us today only because Muslim propagandists are heralding a fictional, idealized, Islam of the mind which never existed to attempt to convince us that Islam is something which it really isn't a religion of peace, enlightenment and tolerance.
As for commerce, the Vikings were traders who engaged in commerce all over the known world, and their social system was well-developed.
But this doesn't make them people who you'd want living next door to you.