I need to show an example of when it would be beneficial to choose 1 discount on an item ,then choosing a series of discounts on that same item.

Compare a single discount of 20% versus two successive discounts of 10% each. If the item originally costs $1.00, a 20% discount is worth $0.20 off, so the final price is $1.00 - $0.20 = $0.80. On the other hand, if you apply two 10% discounts in succession, the first discount is worth $0.10 (10% of $1.00), so after that first discount the pricce is $0.90. Now take another 10% off, which means the second discount is worth only $0.09 (10% of $0.90), and thef inal price after applying the second discount is $0.90 - $0.09 = $0.81. So you can see that for the consumer a single discount of 20% is better than two successive discounts of 10% each.