(5,625 * 1 1/3 - 3 11/18 : 5/9) : 1 2/3 = 0,6
1) 5,625 * 1 1/3 = 5 5/8 * 1 1/3 = 45/8 * 4/3 = (15*1)/(2*1) = 15/2 = 7 1/2
2) 3 11/18 : 5/9 = 65/18 * 9/5 = (13*1)/(2*1) = 13/2 = 6 1/2
3) 7 1/2 - 6 1/2 = 1
4) 1 : 1 2/3 = 1 : 5/3 = 1 * 3/5 = 3/5 = 0,6
Ответ: 3/5 или 0,6 (в десятичных дробях).
Пояснения:
0,625 = 625/1000 = 5/8 - сократили на 125
1 целая 1/3 = (1*3+1)/3 = 4/3
3 целых 11/18 = (3*18+11)/18 = 65/18
1 целая 2/3 = (1*3+2)/3 = 5/3
3/5 = 6/10 = 0,6