спасите пожалуйста, умоляю

1) 2 - 1 11/35 = 1 35/35 - 1 11/35 = 24/35   
2) 24/35 : 9/25 = 24/35 * 25/9 = 40/21 = 1 19/21   
3) 1 13/14 - 1 19/21 = 1 39/42 - 1 38/42 = 1/42   
4) 1/42 + 4/21 = 1/42 + 8/42 = 9/42 = 3/14