What is wrong with this question and what kind of mistake it is. The formula is wrong, not a question of doing it once, but a question of doing it ten times and twenty times. If it is a calculation error, do more questions; Practice more and make fewer mistakes.

If you forget to fill in the unit and the answer uses some minor questions such as false scores, you don't have to do the questions. But remember this lesson.

The best way to learn mathematics is to do more problems, there is no shortcut. Only by doing more exercises can practice make perfect and master the concepts. This is the secret of learning.