No, unless it's in a graduate scheme where that is necessary and you don't have evidence of that in your current degree (e.g. you want to apply to some mathematical modelling based role in an engineering firm...which you wouldn't be aiming for with a humanities degree anyway). If the grad scheme in question doesn't rely on that (e.g. law training contracts, among many others) then it won't matter. The job description for the grad scheme should make it clear what they are looking for in candidates and whether specific numerical skills are needed. In general only basic numeracy and proficiency with standard office packages is probably presupposed. Plus many humanities degrees now increasingly include quantitative options or required modules to develop a wider range of soft skills anyway (see the many "quantifying history" type modules at many universities for example).
Anecdotally even in many ostensibly quantitative fields you don't need much if any quantitative background to the level of a STEM degree; I know someone who did history and politics in undergrad and then went on to become an accountant at a big 4 firm. Investment banks regularly take on people from a wide range of degree backgrounds.