I have stumbled upon an easier alternative to the successive gain/loss types of sums. Instead of doing calculations like 1.15 x 1.15 for a sum what involves successive profits of 15% you can try the following :

Question: Product P is marked up for a profit/loss of 15% and another profit/loss of 15% is made during a season sale etc..What

is the total profit on the product - instead of multiplying numbers like 1.15 x 1.15 (which can be painful if you are in a hurry,

you can follow this general observation that I have come up with while working on such calcuations one day!!

a. profit 15% + profit of 15% = add (15 +15) + (1.5 x 1.5) = 32.25 (total profile)

b. 15 profit + 15% loss = subtract loss from profit (15 -15) - (1.5 x 1.5) = -2.25 ( loss of 2.25)

c. 15% loss + 15 % profit = same as b.

d 15% loss + 15 % loss = 15 + 15 - (1.5x 1.5) = 27.75 ( total loss )

For the first part: Add/subtract the whole numbers beased on whether they are gain/loss.

a. gain, gain = gain + gain

b. gain, loss (and vise-versa) = gain - loss

c. loss, loss = loss + loss

Whenever there is a LOSS invloved always subtract the second part, (1.5 x 1.5), from the first part.

Also, the second part is derived by moving the decimal on the original numbers one place to the left.

I have found it to work with all numbers. It even can be used for compunt interest problems.

Disclaimer: I have not tested this against any mathematical principle. It works for me so thought I would share you you folks

Let me know your thoughs!