How do you figure percent change?

Answer 1

You have your original amount and a new amount. Take whichever is the larger and subtract from the smaller to find the amount by which the original has changed. Now divide this difference by the original amount and multiply by 100 to find the percentage change.

An example.

I have 50 marbles. I am given another 5 marbles (making 55 in total). So...

55 - 50 = 5

5/50 = 0.1

0.1 * 100 = 10

So I now have 10% more marbles than I did before.

Of course if I had, let's pretend, not been given 5 more marbles but had in fact lost 5 marbles, then it would still be a 10% change (in the first part of the calculation above we would do 50 - 45 and still end up with 5), but I would have 10% less than before.