If a sample of coke is 95% carbon by mass, determine the mass of coke needed to react with 1.0 ton of copper (ii) oxide.. 2cuo(s)+c(> 2cu(s)+co2(g)

so thus far i have:
1 ton cuo = 907,185g cuo
907,185g cuo * (1mol cuo/79.545g cuo) = 11404 mols cuo (rounded) [11404.676]
11404 mols cuo * (1 mol c/2 mol cuo) = 5702 mols c (not rounded - no need)
5702 mols c * (12.0108g c/1 mol c) = 68485g c (rounded) [68485.5816]
68485g c * 0.95 = > > 65060.75g c< < (not rounded -exact)
[should i not have rounded? ]
here's what someone else gave

1.0 ton x (2000 lb / 1 ton) x (1 kg / 2.2 lb) x (1000 g / 1 kg) = 9.09x10^5 g cuo

9.09x10^5 g cuo x (1 mol cuo / 79.5 g cuo) x (1 mol c / 2 mol cuo) x (12g c / 1 mol c) x (1 g coke / 0.95 g c) = 7.2x10^4 g coke to two significant digits

the difference being that he used scientific notation for the 1 ton in

which is correct?