Almighty X 10

From Intercross:
Being left alone on Christmas Eve, Ten is mad; her brothers have all cancelled on her. But then a strange boy comes to the rescue and claims that his name is No. 10?! After the strange night, she wakes up to find a name tag of the boy who is named Tohga. With determination to find him in her mind, she sets foot to find him and eventually ends up in the very school that he is from.