In mainland China, when you enter a restaurant, a waitress or waiter will ask you, “Jǐweì?” (几位？) “How many people in your party?” Jǐ means “how many” and weì is a measure word for “guest.” It is also the first character in the word for seat.
You can answer in two ways: (1) sìweì (四位) “four seats or guests” or (2) sìgerén (四个人) “four persons.”
The people in Taiwan are a little more superstitious. They avoid saying the word for four, sì, because it sounds like the word for “death” in Chinese. It wasn’t long ago that you could not find a 4th floor button on the elevators, either! They avoid saying “four” in the restaurant by saying, sān jiā yī (三 加 一) “Three plus one.” Obviously, you would never give a cash gift of forty dollars or celebrate a birthday at 40 years old there.
You can learn more Chinese for getting seated in restaurant here in this free lesson.
Here’s a video lesson I found on Youtube.