1) 18 21/53 × 27/34 = (975×27)/(53×34)=
=26325/1802= 14 1097/1802
2)14 1097/1802 × 42 2/5 = (26325×212)/(1802×5) =
=(5265×2)/(17×1)= 10530/17= 619 7/17
3) 619 7/17 × 47 2/9 = (10530×425)/ (17×9) =
=(11702×5)/(1×1)=29250
4) 125/161 × 8 216/617 = ( 125×5152)/(161×617)=
= (125×32)/(1×617) = 4000/617=6 298/617
5) 6 298/617 × 15 17/40 = (4000×617)/(617×40) = 100
6) 100 × 22 31/36 = (823×100)/(36×1)=
= (823×25)/(9×1)= 20575/9 = 2286 1/9
7) 29250 - 2286 1/9 = 26963 8/9
Ответ. 26963 8/9 .