The numbers become the basis for the analysis of the data collected during a research project. They tell us whether or not there is evidence to prove the research question or hypothesis. For example, if you have a target number of participants in your project you might report this number in your findings.
If your numbers are high or low, that might indicate the “power” of your findings. If you report your assertion happened in three out of five cases studied, it might not appear as convincing as if you reported 270 out of 300 cases studied. Clearly, the numbers show how extensive your study is.