Chang Xia ordered a number.

Chang Xia ordered a set meal for five people.

Long summer is usually in May of the solar calendar, and the riddle uses long summer to type a number, which is of course 5. The seventh solar term in the twenty-four solar terms of the lunar calendar and the first solar term in summer. When the sun reaches 45 degrees of the Yellow Meridian, it is a long summer, and the date is May 5 or May 6 of the Gregorian calendar every year. The long summer heralds the change of seasons and the official start of summer.