A pot of steamed bread, 38 Xiaoming and his five classmates each ate four. How many steamed buns are left?
18. According to relevant information, 38 Xiaoming and his five classmates each ate four steamed buns in a pot, leaving 4*5=20, 38-20= 18 steamed buns. Formulas, in mathematics, physics, chemistry, biology and other natural sciences, use mathematical symbols to express the relationship between several quantities. It is universal and applicable to all similar problems.