4,5[47,375-(26 1/3- 18*0,75)*2.40,88]/(17,81:1,37-23 2/3:1 5/6)

4,5 * [47,375 - (26 1/3 - 18 * 0,75) * 2,4 : 0,88]/(17,81 : 1,37 - 23 2/3 : 1 5/6) = 612 целых 9/16
 
1) 18 * 0,75 = 13,5 = 13 1/2
2) 26 1/3 - 13 1/2 = 26 2/6 - 13 3/6 = 25 8/6 - 13 3/6 = 12 5/6
3) 12 5/6 * 2,4 = 77/6 * 24/10 = (77*4)/(1*10) = 308/10 = 30,8
4) 30,8 : 0,88 = 35
5) 47,375 - 35 = 12,375
6) 4,5 * 12,375 = 55,6875
7) 17,81 : 1,37 = 13
8) 23 2/3 : 1 5/6 = 71/3 : 11/6 = 71/3 * 6/11 = (71*2)/(1*11) = 142/11 = 12 10/11
9) 13 - 12 10/11 = 1/11
10) 55,6875 : 1/11 = 55,6875 * 11/1 = 612,5625 = 612 целых 9/16