Mixed and Absolute Cell References. To avoid this problem created by the relative cell reference A7, mixed and absolute cell references can be used, which prevent all or part of a cell reference in a formula from changing as it is copied. Absolute and mixed cell references are created by adding dollar signs ($) to a cell reference. For example, in the image above, the cell reference $A$6 in the formula in cell B2 is an absolute cell reference and $A2 is a mixed cell reference.
The point of sale (POS) is the time and place where a retail transaction is completed. It is the point at which a customer makes a payment to the merchant in exchange for goods or after provision of a service.
The point of sale is often referred to as the point of service because it is not just a point of sale but also a point of return or customer order.Additionally, today POS software may include additional features to cater for different functionality, such as inventory management, CRM, financials, warehousing, etc. retail point of sale system typically includes a cash register (which in recent times comprises a computer, monitor, cash drawer, receipt printer, customer display and a barcode scanner) and the majority of retail POS systems also include a debit/credit card reader.