Выполните действия:

5/6*9/15-5/12*4/15; 7/18*9/14+1/3*6/7; 9/20*2/3+5/14*7/25; 3 3/4*2/5-3 6/25*5/27; 1 17/28*14/9+14/25*5/7

1) 5/6*9/15-5/12*4/15;

1/2-1/9=9/18 - 2/18 = 7/18

2) 7/18*9/14+1/3*6/7

1/4+2/7=7/28+8/28 = 15/28

3) 9/20*2/3+5/14*7/25

3/10 + 1/10 = 4/10 = 0,4 или 2/5

4) 3 3/4*2/5-3 6/25*5/27

3/2-9/15 = 45/30 - 18/30 = 27/30

5) 1 17/28*14/9+14/25*5/7

5/2+2/5=25/10+4/10=29/10 = 2,9