The problem asks you to find $$\lfloor 0.785\rfloor$$. The definition of $$\lfloor x\rfloor$$ for an arbitrary real $x$ is given in the first paragraph of the problem. If you don't understand that definition, I suggest an exchange. You give a detailed explanation of what you do and don't understand in that sentence. This helps me understand what parts of explanations may not be clear, and helps me hopefully explain things better in the future. In exchange, I describe the confusing parts. (I am not the author of the problem, of course.)