How to calculate the phone bill?

For calls, charge per minute. For example, if you call 10 minutes, the cost is 10 minutes multiplied by the rate per minute. Some operators also offer monthly packages, so you can make unlimited calls as long as you pay a fixed monthly fee. For short messages, it is calculated according to the method of charging each time. For example, sending 10 short messages, then the cost is 10 times the rate of each short message. Similarly, some operators also offer monthly packages, so you can send SMS unlimited as long as you pay a fixed monthly fee. For data usage, it is charged per GB.