Как решить- 1 ) 4/9+5/6-3/4 - 2)
6/7-1/4+5/14 -3) 11/12-1/9+1/4

12 7/15-9 3/4+5 11/12= 12 28/60-9 45/60+5 55/60= (12-9+5)+(28/60-45/60+55/60)= 8 38/60= 8 19/30

1) 4*4/36+5*6/36-3*9/36= 16/36+30/36-27/36=46/36-27/36= 19/36;2) 6*4/28-1*7/28+5*2/28= 24/28-7/28+10/28=27/28;3) 11*3/36-1*4/36+1*9/36= 33/36-4/36+9/36=38/36= 19/18= 1цел 1/18.