Typical questions: multi-digit numbers, age, indefinite equations, remainders

Look at the options: The options are a set of numbers, which can be converted into a set of numbers

Two items left: When there are only two items left, substitute one item to get the answer

Age problems; multi-digit problems; indefinite equation problems; sum and difference ratio problems; complex equation problems

First exclude: mantissa, size, odd and even, multiples

Substitute again: easy to calculate, the most valuable problem

Scope of application

Specific usage

Scope of application

Specific usage

divisibility rule

Let the unknowns

Substitution exclusion

The unknown number must be an integer

The ratio of unknown numbers must be an integer

No specific value appears in the question stem

In a three-quantity relationship such as A=B*C, at most one of the quantities can have a specific value.

engineering issues

itinerary issues

economic profit issues

solution problem

Assign values ​​to the invariants in the question

Assign a common multiple to the given number

Assign values ​​according to the given proportional relationship

Assignment should be as easy to calculate and resolve as possible

Mixing ratio problem

Concentration mixture, average mixture, profit margin mixture, discount mixture, specific gravity mixture, growth rate mixture, etc.

Write both ends before mixing, write the middle after mixing

Distance and quantity are inversely proportional, and the calculation of parts cannot be inverse.

The ratio of mixed concentration to solution mass

Mixed average: For example, GDP per capita corresponds to the ratio of the number of people

Mixed profit margin:ratio of corresponding costs

Mixed discounts, corresponding pricing ratio

Mixing proportion, corresponding to the ratio of the overall amount

Mixed growth rate, corresponding to the ratio of base period volume