There is an episode of The Office where Michael gives a business five "10% off" coupons and forgets to write "Coupons cannot be combined." In the episode, the business claims they can use the coupons for 50% off.
But that got me thinking, even if you forgot to write "Coupons cannot be combined," is there an argument that the coupons would have to be used sequentially rather than stacking them? In other words, instead of saying the discount is 10+10+10+10+10=50%, could you argue that the end price should actually be 90% X 90% X 90% X 90% X 90% = 59%, for a discount of 41%?
Can you "stack" coupons as in the episode, or do they have to be applied one at a time?