Cashiers are a necessary occupation in various industries including retail, food service and business operations. Not only do cashiers need customer service skills, they also must possess basic math skills in order to perform the job correctly. Many cash registers commonly do the math for the operator but there are times when technology fails, requiring the cashier to manually and accurately configure the customer's subtotal, discount, tax and total.

Addition

To accurately combine the amounts of any customers items, the cashier must have the ability to add amounts containing up to two decimal places which are common when dealing with monetary values. To add money amounts, write each dollar value in a list ensuring that the decimal place lines up opposed to the numbers. Add each place value and bring down the decimal to ensure that the customer's total is correct.

Subtraction

When customers change their minds at the last minute, demonstrating "buyer's remorse" and wishing to put something back on the shelf, a cashier may have to subtract that amount from the total. Subtraction is also used to discount items or the monetary total of all items using a coupon that designates a certain dollar amount off. Take the coupon or returned amount from the total prior to configuring sales tax on the subtotal.

Multiplication

When customers present a percentage off coupon during the payment process, a cashier may have to use multiplication skills to configure the actual dollar amount to be subtracted from the subtotal. Change the percentage amount from the coupon into a decimal by moving the decimal place after the percentage number two place values to the left. As an example, 30 percent as a decimal would equal 0.30. Multiply the decimal by the subtotal to find the dollar amount to be subtracted from the original subtotal.

Division

Division can be used by cashiers when configuring how much certain items cost when grouped during a sale. For example, when t-shirts are discounted for customers at a buy two, get one free sale and the customer needs to know how much each shirt actually costs, a cashier would use division. Add the cost of the two shirts together and divide that by three to find out the price of each shirt.