-
Zhang Zhenlin
Mathematics comes from life and is used in life. The "discount sale" in the sales question can link mathematics with life.
Let's go Through teaching, students can fully feel that mathematics comes from life and is used in life. Students are willing to take such classes.
Learning is also willing to learn. But in teaching, if students want to understand how to solve the sales problem, they must first understand.
What do you mean by dosage?
Two equivalent levels obtained from the basic relationship between quantity and quantity, what is the relationship between quantity and quantity?
Department. Details are as follows:
Quantity used: purchase price, selling price, marked price, profit and profit rate. What they mean is:
Purchase price: the price of the purchased goods. (sometimes called cost price)
Selling price: the selling price when selling goods.
List price: the price indicated when selling goods.
(sometimes called original price)
Profit: net income from the sale of goods.
Profit rate: the percentage of profit to cost.
Discount rate: the percentage of sales at a certain discount on the basis of the list price.
The basic relationship between quantity:
price
=
List price (original price) × discount rate
or
price
=
purchasing price
+
Profits,
%
purchasing price
profit
profit rate
100
8? seven
8? eight
profit
=
Sales price-purchase price (cost price) or profit.
=
Purchase price (cost price) × profit rate,
Two equivalent relationships are obtained from the basic relationship between quantity and quantity.
List price (original price) × discount rate
=
purchasing price
+
profit
Sales price-purchase price (cost price)
=
Purchase price (cost price) × profit rate
What does control mean?
What is the basic relationship between quantity and quantity, and what do you get from it?
When there are two equal relationships, there are only two sales problems: one is to solve the basic relationship of consumption;
One is to solve the problem with two equal relationships. Details are as follows:
Solve the basic relationship between doses;
(
1
), original price
100
Yuan's goods are smashed.
eight
The discount price is
Yuan;
Use: sales price
=
List price (original price) × discount rate
(
2
), purchase price
100
Yuan's goods are here.
150
Yuan sold, the profit is
Yuan, the profit rate is
profit
=
Sales price-purchase price (cost price)
%
purchasing price
profit
profit rate
100
8? seven
8? eight
For the above types of questions, two quantities are known to find the other quantity.
This paper mainly investigates the basic relationship between students and quantity.
Degree of mastery of the department. In teaching, students can easily solve such problems. But a number of three or more.
As soon as it appears, students are full of doubts, and it is difficult to find out the equivalence relationship and list the equations. I am also good at teaching.
Very headache. I really want to tell the students clearly, but I can't break through the previous treatment, which is very
Most students are still unable to solve such problems skillfully. But when I was talking about a sales problem, I suddenly found out.
Methods for handling three or more quantities.
They are the basic relations between the quantities mentioned above.
Two equivalence relations are obtained.
By: sales price
=
List price (original price) × discount rate
or
price
=
purchasing price
+
profit
Get: list price (original price) × discount rate
=
Purchase price (cost price)
+
Profit? 6? 7? 6? 7①
By: profit
=
Sales price-purchase price (cost price) or profit.
=
Purchase price (cost price) × profit rate
D: selling price-purchase price (cost price)
=
Purchase price (cost price) × profit rate? 6? 7? 6? 7②
Their appearance solved my previous confusion. In teaching, I see that as long as students can master the basic quantity.
The relationship between them, in the corresponding quantity problem, two equal relationships, students can solve this kind of problem quickly and make a list.
Cheng. Examples are as follows:
Solve problems with two equal relationships:
(
1
)
Increase at cost price
40%
After bidding, press it again.
eight
Discount sales, so that every piece can be earned.
15
Yuan. This kind of clothes
What is the cost price of each piece?
Analysis: What is the problem? What is the cost of each piece of this kind of clothes?
X
Yuan.
Using the equivalence relation ①, the marked price (original price) × discount rate
=
purchasing price
+
Profit? 6? 7? 6? 7 (1) Find the corresponding quantity, unknown quantity.
The quantity of is expressed by a known quantity. So the equation can be listed quickly.
List price (original price) × discount rate
=
Purchase price (cost price)
+
Profit? 6? 7? 6? 7①
(
X+X
%)
×
80
%
= X + 15
(
2
)
The price of a commodity is
132
Yuan, if the price drops to
nine
It can still be profitable to sell at a discount.
10%
(relative to the purchase price)
What is the purchase price of this commodity?
Solution: Let the purchase price be
x
Yuan.
Using equivalence relation ②: selling price-buying price (cost price)
=
Purchase price (cost price) × profit rate? 6? 7? 6? 7②
132
×
90
%
-
X = X
×
10%
(
three
)
The purchase price of a commodity is
2000
Yuan, the price is
3000
Yuan, the store requires a profit rate of not less than
5%
about
The price is discounted. If you want to buy this product, you can bargain with the salesman, and he can at least call.
What's the discount for this product?
Solution: Set the minimum play.
x
Fold.
Using equivalence relation ②: selling price-buying price (cost price)
=
Purchase price (cost price) × profit rate? 6? 7? 6? 7②
3000
×
10
X
-
2000 = 2000
×
5%
Through the practice of examples, I found that the success rate of students solving such problems can be achieved.
90%
Above, obviously improved.
The efficiency and success rate of doing problems have been improved. But not yet.
10%
% of the students can't solve this problem, mainly because they
The relationship between basic quantities, the corresponding relationship of quantities in the problem and the familiarity of the two equivalent relationships obtained. Through this
Last class, I found that the good way to solve many problems is at our writing end, depending on whether we pay attention to it or not.