The COVID-19 pan­dem­ic was a sad but per­fect oppor­tu­ni­ty to engage with math­e­mat­ics. Sud­den­ly, we were all con­front­ed with inci­dence rates, over­whelmed with sta­tis­tics, and had to deal with prob­a­bil­i­ties. On a very per­son­al lev­el, with the like­li­hood of get­ting infect­ed or the ques­tion of how reli­able the new­ly devel­oped COVID-19 tests were. Ques­tions that could decide on free­dom, health, and for some even on life and death.