8       5

0.8*5/8 = ----- * ---- =5/10 =0.5

                  10      8

5:2.5 = 2

числитель = 0.4 +8*(5-0.5) - 2 =0.4 + 36 -2 = 34.4

(1+7/8)*8 = 8 +7 =15

2.6: (2/3) = 2.6* 3/2 = 3.9

знаменаталь = (15 - (8.9 - 3.9))*34.4 = (15-5)*34.4 = 10*34.4

дробь=34.4/(10*34.4) = 1/10 = 0.1

(0.4+8*(5-0.8*5//8)-5:2 1//2)/((1 7//8*8-(8.9-2.6:2//3))*34 2//5)=(0.4+36-5:(2 1//2))/(((1 7//8)*8-(8.9-2.6:(2//3)))*(34 2//5))=(36.4-5:(5//2))/(((1 7//8)*8-(8.9-2.6:(2//3)))*(34 2//5))=(36.4-2)/(((1 7//8)*8-(8.9-2.6:(2//3)))*(34 2//5))=34.4/(((15//8)*8-(8.9-2.6:(2//3)))*(34 2//5))=34.4/((15-(8.9-2.6:(2//3)))*(34 2//5))=34.4/((15-5)*(34 2//5))=34.4/(10*(172//5))=34.4/(10*34.4)=34.4/344=0.1

// - черта дроби