In mathematics, formula refers to the formula listed in the calculation of numbers (or algebraic expressions), including numbers (or letters instead of numbers) and operation symbols (four operations, power, root, factorial, permutation and combination, etc. ).

According to the different calculation methods, the formulas are generally divided into horizontal and vertical.

Unlike expressions, expressions are expressions that connect data of the same type (such as constants, variables, functions, etc.). ) Use operation symbols according to certain rules, and expressions are expressions that connect numbers through operation symbols to calculate results, and need an equal sign.

Addition is one of the four basic operations, which refers to the calculation of combining two or more numbers and quantities into one number and quantity. The symbol of addition is the plus sign "+". Connect items with a plus sign when adding.

Addition (usually indicated by the plus sign "+") is one of the four basic arithmetic operations, and the others are subtraction, multiplication and division. For example, in the picture below, * * * has a combination of three apples and two apples, and * * * counts as five apples. This observation is equivalent to the mathematical expression "3+2 = 5", that is, "3 plus 2 equals 5".