All problems accept answers in the ways that they are taught in that topic, with technical variations. A student should know how to write the answer properly if they have studied the topic. The Topic Text provides a comprehensive lesson on the material, and should be studied in addition to the multimedia for a thorough understanding.
If it is a technical issue (like a comma) the problems are programmed to account for that as much as possible.
For example, if the answer is “3,257” the problem accepts “3,257” or “3257”.