Ответ:

  1. \(7,4+2,1=9,5\).
  2. \(7,4+1,6=9\).
  3. \(6,84-5,23=1,61\).
  4. \(7,37-5,14=2,23\).
  5. \(8,271-6=2,271\).
  6. \(9,351-8=1,351\).