If something is one, two is twice the number one, and half is
half of whatever.
50% can be writen as 0.5 or 1/2 ... its the same.
Probability of someting to happen is the positive outcomes vs all
for example in the tails game with the coin head is 1 from the 2
so to get head its 1/2=0.5 or 50% ...
if i bring heads, the next time it doesnt mean that i have 100%
posibility to win if i lost, in every game i have 50% to win.