If you receive vouchers (from, say, sodexo) which have a fixed value and you
need to pay a certain amount, you may wonder how many vouchers you have to spend
and how much tip you may be giving with an additional voucher.
Features:
* Enter price you need to pay
* Select the maximum number of vouchers you carry
* It shows how much you still have to pay
* Or how much extra you'd give with an additional voucher
