Which one is correct?

You'd better go over your maths notes.
You'd better go through your maths notes

Either one will work fine.

Both expressions are correct, but they have slightly different meanings and usage.

"You'd better go over your maths notes" means you should review or study your maths notes. It implies that you should review the content in a general or overall way. It is often used when you want to refresh your memory or ensure you have a good understanding of the material.

"You'd better go through your maths notes" also means you should review your maths notes, but it suggests a more detailed and thorough examination of the content. It implies that you should go through each page or section in a systematic manner, paying attention to the details and ensuring you fully understand the material.

To decide which expression is more appropriate for your situation, consider the level of detail and thoroughness you wish to achieve. If you just want to refresh your memory or get a general understanding, "go over" would be a suitable choice. If you want to engage in a more thorough review, ensuring you understand each aspect, "go through" would be a better choice.

In summary, "go over" means to review in a general way, while "go through" means to review in a more detailed and comprehensive manner.