The introductory workbook for the Natural Science Students contains many questions designed to check your skills in the fundamental mathematics needed to succeed in the Natural Sciences Tripos at Cambridge University. Here we provide a set of stemNRICH problems designed to complement these activities and develop your scientific mathematical skill. These stemNRICH problems are roughly grouped into subject area according to the workbook, but there is a natural overlap between some of these areas. These problems are relatively subject-agnostic -- not particularly directed towards chemistry, physics or biology. You might wish to look at bioNRICH, physNRICH or chemNRICH for mathematical activities focussed on areas of particular interest to you. If you need any help, please go to the main stemNRICH page for support.