Вычислите:а) (3\4+1\6):3+(5\6-1\2):9=?б) ( 3\4-5\12)*3-1\16:1\8=?

а) (3/4 + 1/6) : 3 + (5/6 - 1/2) : 9 = 8 1/4. 

1). 3/4 + 1/6 = (3 * 3) / (4 * 3) + (1 * 2) / (6 * 2) = 9/12 + 2/12 = (9 + 2) / 12 = 11/12; 

2). 11/12 : 3 = 11/12 * 1/3 = (11 * 1) / (12 * 3) = 11/36; 

3). 5/6 - 1/2 = 5/6 - (1 * 3) / (2 * 3) = 5/6 - 3/6 = 2/6 = 1/3;

4). 1/3 : 9 = 1/3 * 1/9 = (1 * 1) / (3 * 9) = 1/27; 

5). 11/36 : 1/27 = 11/36 * 27/1 = (11 * 27) / (36 * 1) = 297//36 = 99/12 = 33/4 = 8 1/4. 

б) (3/4 - 5/12) * 3 - 1/16 : 1/8 = 1/2. 

1). 3/4 - 5/12 = (3 * 3) / (4 * 3) - 5/12 = 9/12 - 5/12 = 4/12 = 1/3; 

2). 1/3 * 3 = 3/3 = 1; 

3). 1/16 : 1/8 = 1/16 * 8 = 8/16 = 1/2; 

4). 1 - 1/2 = 1/2.