Being the most popular answer doesn’t make it the right one. Ask any math teacher.

Agreement measures how many people share an assumption, not whether the assumption holds. Common errors are common precisely because they are intuitive, which means the wrong answer often has more support than the right one and arrives faster. Consensus is information, just not the kind people take it for.

When everyone around you agrees, ask what they are all relying on. Look for the person who reached a different answer and find out how. You are not obliged to be contrary, only to check whether anyone actually did the work or whether the answer was inherited.