This chapter tries to motivate why 21st century computer scientists should know about quantum computing. To this end, we look at an important yet easily understood combinatorial optimization problem, namely the subset sum problem or SSP for short. As it is combinatorial, the SSP is generally difficult even for modern artificial intelligence models. We discuss why this is and why quantum computers may have an edge. To be able to see this, we show how to set up the SSP for quantum processing. This involves a first look at binary vectors and the notion of quadratic unconstrained binary optimization problems (QUBOs). In passing, we thus already encounter much of the terminology and concepts used in later chapters.