High School > Math > Number Operations
In the earliest days of elementary school, students often learned about the basic number operations: addition and subtraction. One plus one equals two, two plus two equals four, and so on. Then from one digit addition and subtraction, they would go to two digits, then three digits as they progress through grade levels.
Later on, they would also learn about multiplication and division. Multiplication, as many teachers would say, is just repeated addition, while division is just repeated subtraction. Again, it starts with one digit multiplication, where students usually memorize multiplication tables. Then they move on to two digits, three digits, and long division. Multiplication and division are more complicated, so they require higher grade levels before being taught.
Students would also be taught how to translate word problems into mathematical equations involving operations. For example Sam had twenty apples, then Harry took five of them. How many apples does Sam have left? This would be 20 - 5 = 15; therefore, Sam would have 15 apples left afterward. This skill of turning word problems into simple mathematical models is one of the most practical skills that students can learn as they study number operations.
As students approach high school and college levels, they should already have mastered these four basic operations. They will find these useful not just in their more advanced subjects, but also in daily life. Algebra, calculus, statistics, and trigonometry make use of number operations, and so does banking and business. Even cooking can make use of number operations, like when adjusting recipes to serve a certain number of people. See, daily home life also involves some aspects of math.
For the most part, everyone knows their basic number operations by heart. Even in today’s age of phones that can handle scientific calculations, having those basic math skills always ready in people’s minds is a great asset that can truly help them get by in life.