2nd chances to get a question answered correctly

My kids love using Khan Academy. The only thing that makes them frustrated is that, when they submit a wrong answer, they do not have a second chance to rethink or fix to get it correct. Beast Academy is another math learning website. When we submit a wrong answer in Beast Academy, it will highlight the half circle (instead of the whole circle), meaning that you have a second chance to fix it. This is very important for kids who know how to solve the question but just are not very careful enough. 

Do you think this potential feature is important? Please vote!