What is the most popular math exam?

Could you please elaborate on what you mean by "the most popular math exam"? Are you referring to a specific type of exam, such as those taken for college admissions or professional certifications? Or are you asking about the most commonly taken math exam globally? Additionally, popularity can be subjective and vary based on region, education level, and personal preferences. Clarifying these details would help me provide a more accurate answer to your question.