97 1/6 + 11/39 - 6 8/13 -10/21 × (9/16 +3,075 × 0,5) : 1/83=

97 1/6 + 11/39 - 6 8/13 -10/21 × (9/16 +3,075 × 0,5) ÷ 1/83= 7 5/6
4)1÷1/83=1×83=83
5)97 1/6  +  11/39 = 583/6  +  11/39 =(583 × 13  +  11 × 2)/78 = 7579/78 +  22/78 =  7601/78 = 97 35/78
6)97 35/78  -  6 8/13 = 7601/78  -  86/13 =(7601 × 1  -  86 × 6)/78 = 7601/78  -  516/78 =  7085/78 = 545/6 = 90 5/6
7)90 5/6  -  83 = 545/6  -  83 =(545 × 1  -  83 × 6)/6 = 545/6  -  498/6 =  47/6 = 7 5/6