Count every car first.

4800/20

Count 25 more cars.

(4800/20)*25

Calculate the original income and new income.

(4800/20)*25+4800

Method 2: (that is, your method 2)

Count every car first.

4800/20

Calculate the total number of vehicles after the increase.

20+25

Recalculate total income

(4800/20)*(20+25)

Method 3: (that is, your method 3)

First, calculate the proportional relationship between the original number of vehicles 20 and the increased number of vehicles (20+25).

(25+20)/20

Even if it is many times more than before.

Calculate the amount of money after adding the above multiples to the original 4800.

4800*[(25+20)/20]

Method 4: (that is, your method 4)

First, figure out how many times the increase is.

25/20

Calculate how many times the increased income is the original income.

(25/20)*4800

Finally, calculate the sum of the original income and the increased income.

(25/20)*4800+4800

The teacher said these were wrong? Unreasonable = =b)

Method 5:

Suppose you add 25 cars and do it twice.

The first increase in vehicles is the same as the original 20 vehicles, that is, the income is doubled.

4800*2

Added (25-20) cars for the second time.

Count every car again.

4800/20

I'm calculating the second increase in income.

(4800/20)*(25-20)

The final total is the final test.

(4800*2)+(4800/20)*(25-20)

Method 6:

Suppose you add 25 cars and do it twice.

The first increase in vehicles is the same as the original, and the income doubles.

4800*2

Added (25-20) cars for the second time.

Calculate the original 20 times and increase it for the second time.

The proportional relationship of quantity is

(25-20)/20

So the second increase in income is

4800*[(25-20)/20]

The final total is the final test.

4800*2+4800*[(25-20)/20]

If you can use equations, there are more.

If equations can be used, there will be more and more.

One trick of using equations is to add things that are not necessary at all.

You can think more.

Actually, it's just that the formula has changed.

This is the "quality education" in primary schools?

No wonder I can't accept it.

Our education system