At the point of sale, the merchant would calculate the amount owed by the customer and indicate the amount, and may prepare an invoice for the customer (which may be a cash register printout), and indicate the options for the customer to make payment.
Performing push-ups works a variety of muscles in your upper body, including specific muscles within your abdomen, chest, shoulders and upper arms. You can vary your technique by placing your hands at different widths to emphasize one area over another.
The push-up excercise requires many muscle groups, but the primary muscle group has to be the chest muscles. the chest includes the pectoralis major and minor. These are the 2 large chest muscles and mainly the pushing muscle group of the upper body. As you are pushing and lowering your body during a push up, the pectoralis major is doing most of the work. As a result, these 2 muscles become very strong and can become defined lean muscle after doing push-ups regularly.