42/3-5/9*2 4/7 +0,8*1,25= ответ должен быть 5,25 (2 1/7+1 2/3): 5 мне

[4 2/3 - 5/9 * 2 4/7] / [(2 1/7 + 1 2/3) : 5] + 0,8 * 1,25 = 5,25

1) 5/9 * 2 4/7 = 5/9 * 18/7 = (5*2)/(1*7) = 10/7 = 1 3/7
2) 4 2/3 - 1 3/7 = 4 14/21 - 1 9/21 = 3 5/21
3) 2 1/7 + 1 2/3 = 2 3/21 + 1 14/21 = 3 17/21
4) 3 17/21 : 5 = 80/21 * 1/5 = (16*1)/(21*1) = 16/21
5) 3 5/21 / 16/21 = 68/21 * 21/16 = 68/16 = 4 4/16 = 4 1/4 = 4,25
6) 0,8 * 1,25 = 1
7) 4,25 + 1 = 5,25