I am very good with numbers hence the post. I am trying to figure out how to calculate the percentage of time that my outs will hit.

I've been told by a friend to do the following math. Which vaugely makes sense to me.

1-3 Outs: Outs x 2 = % of hitting
3-11 Outs: (Outs x 2) + 1 = % of hitting
12+ Outs: (Outs X 2) + 2 = % of hitting

(flop 47/outs)
(river 46/outs)

OUTS TURN RIVER
1 2.13% 2.17%
2 4.26% 4.35%
3 6.38% 6.52%
4 8.51% 8.70%
5 10.64% 10.87%
6 12.77% 13.04%
7 14.89% 15.22%
8 17.02% 17.39%
9 19.15% 19.57%
10 21.23% 21.47%
11 23.40% 23.91%
12 25.53% 26.09%
13 27.66% 28.26%
14 29.79% 30.43%
15 31.91% 32.61%
16 34.04% 34.76%
17 36.17% 36.96%
18 38.30% 39.13%
19 40.43% 41.30%
20 42.55% 43.48%
21 44.68% 45.65%

HOWEVER.... I've come across this today and I am completely stumped by the % differences......