((3,86 + 4 3/25) : 2,1 + 10,2 : 8 1/2) * 0,3
1) 3,86 + 4 3/25 = 3 86/100 + 4 3/25 = 3 86/100 + 4 12/100 = 7 98/100 = 7 49/50
2) 7 49/50 : 2,1 = 399/50 : 2 1/10 = 399/50 : 21/10 = 399 * 10 / 50 * 21 = 19/5
3) 10,2 : 8 1/2 = 10 2/10 : 8 1/2 = 10 1/5 :17/2 = 51/5 : 17/2 = 51 * 2 / 5 * 17 = 6/5
4) 19/5 + 6/5 = 25/5 = 5
5) 5 * 0,3 = 5/1 * 3/10 = 3/2 = 1 1/2 = 1,5