umm first you write down the number of zeros (but only the zeros at last if a zero comes in middle or between other numbers, then you must have to multiply it) and then multiply the remaining numbers. I am not good at explaining. ;)
If they paid $0.72 in tax and tax is 6% or .06 then you could create an equation like this: x * .06 = .72 with x representing the original cost of the bracelet. Now you can just solve for x like so: