The color part looks like it was added after grading the b/w handout. Initially it looks to have read “You have six balloons. You have five balloons. How many more balloons are there?”, to which “11” is a legitimate answer.
In your version, you still don’t have 11 more balloons. If you have 6 balloons, then you have 5 balloons, you have 1 less balloon, not 11 more.