Если помоше. поставте 5 звездов

1) 1. 12/19 - 3/19 = 9/19

   2. 9/19 + 7/19 = 16/19

   3. 12 - 3 + 7 = 16, 16/19

   16/19 = 16/19 = 16/19

2) 1. 1 = 13/13

   2. 13/13 - 5/13 = 8/13

   3. 13/13 - 5/13 = 8/13

   8/13 = 8/13 = 8/13