Help me please with 11 and 12( 50 )

1) 53×3=159 км 2) 64×3=192 км 3) 159+192=351 км 4) 600-351=249 км ответ между ними будет 249 км

A lot of teens go in for different kinds of sport. Sport helps them to feel as fit as a fiddle. In both countries there are special programmes for problem teenagers, such as a high-risk activities, for example they are taught to jump out of aeroplanes. But despite the increase in the number of teens participating in sport, the majority of young people still prefer to be spectators. They prefer to be couch potatoes. Watching sports on TV is a popular leisure activity, as is going to football matches on Saturday. Cinemas have been redesigned with four or more screens, each showing a different film at the same time, and a lot of teens like going to the cinemas too.

Joanne Rowling ( July  31, 1965) - an extremely popular English writer, the creator of  Harry Potter novel series (1997-2008) that was translatted into tens of languages, including Russian. The famous author has written may boos about the character of Harry Potter.
"Harry Potter" - is a popular series of novels of the British author Joanne Rowling. Every book expresses a year of life of the main character - a wizard-boy named Harry Potter. The first book was puiblished in England. Seven books have been written by now:
Harry Potter and te Philosopher's Stone
Harry Potter and the Chamber of Secrets
Harry Potter and the Prisoner of Azkaban
Harry Potter and the Goblet of Fire
Harry Potter and the Order of Phoenix
Harry Potter and the Half-Blood Prince
Harry Potter and the Deathly Hallows