How do you calculate percentage gain and loss?

for example, something was $10 and now it is $15. how would you calculate the percentage gainHow do you calculate percentage gain and loss?
For $10, the increase is $5

For $1, the increase is 5/10 = 1/2

For $100, the increase is 100(1/2) = $50

or the increase (gain) is 50 %How do you calculate percentage gain and loss?
15/10=1.5



U gained 50%.