Eric downloads a 10% off any one item coupon and goes shopping at gadgets galore, where he buys a digital camera for $93 and an extra battery for $13.99.

The answer is that his total cost is $96.30

I assume the question is asking how much he paid...?

If so, he has 10% off from 100% of the original price.
100% - 10% means he will pay 90% of the original price.
To find the original price we must add the price of the two items together to get the total price.

$93 + $13.99 = (I will let you do the math.)

Then we must multiply the total price by the percentage he paid (90%).
To do this we must convert 90% into a decimal.
Percent(%) is just a way of saying "Out of 100".
So 90/100 = .90

For the final answer multiply:  .90 * total price = answer.