Numbers & Math

Enemy 1 of 5

A value typed as number can be added, subtracted, multiplied (*), and divided (/), the same arithmetic operators plain JavaScript uses, following the same order of operations (multiplication and division before addition and subtraction, unless parentheses say otherwise).

Store the parts in variables typed as number, then combine them. Because the type is explicit here, TypeScript guarantees that price and quantity can never accidentally hold a string later on — if some other part of the program tried to assign price = "5";, the compiler would reject it immediately.