How is my baby brother destroying my assignment cute?

Answer 1

It isn't and you are justified to feel aggrieved. Your parents/guardians/carers should have intervened to prevent this or reprimanded your baby brother.

When you are feeling calmer try speaking to your parents/guardians/carers in private and tell them how you feel and how much inconvenience your baby brother's actions have put you to and that you are scared this will affect your school results. Just say how you FEEL don't criticize your brother or tell them what they should have done and once you have said this leave them to think about it (leave the room).