A New Way to Show Your Work

I think it would be very beneficial if Khan Academy had a way to edit the screen, so you could underline or circle words in a question or label a math problem. It would help people focus on what the question is asking or the units. If someone had a touch screen laptop, it would be very beneficial, and they could show their work. It would also help people feel like they are actually taking the test. If this is not a feature that can be added soon, could you at least have and underline function and different highlighting colors that can be used in reading passages and the overall questions? Thank you.