A column distinguishes two objects,

Two columns are filled with a known amount,

Keep up with the unknown,

Fill in the final quantity of a set of formulas,

The last number must be equal,

The party of equal relations.

Extension: classification of application problems

In primary school mathematics, the practical problems with quantitative relations are described in language or words, and the problems formed in this way are called application problems. Any application problem contains two parts. The first part is known conditions (conditions for short), and the second part is seeking problems (problems for short). The conditions and problems of application questions constitute the structure of application questions.

Application problems can be divided into general application problems and typical application problems.

An application problem with two or more operations without specific solving rules is called a general application problem. An application problem that has a special quantitative relationship and can be solved by specific steps and methods is called a typical application problem.

(Application problems in primary school are generally solved by arithmetic, and only a few are solved by equations and proportions; All application problems in junior high school should be solved by equation method)