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What are the quantitative relations in the math application problems in grade three?
What are the quantitative relations in the math application problems in grade three?

First, the relationship between unit price, quantity and total price

1.

lead into/introduce

There are various quantitative relations in production and life.

.

What are the common quantitative relations in multiplication application problems?

.

2.

example

1

: unit price × quantity

=

total

( 1)

example

1.

Every pencil

five

Jiao, buy

three

Branch usage:

5×3= 15 (angle

)

15

corner

= 1

Yuan dynasty (1206- 1368)

five

corner

Basketball players

70

Yuan, buy

2

Personal use:

70×2= 140 (yuan

)

Fish per kilogram

nine

Yuan, buy

four

Kilogram:

9×4=36 (yuan

)

(2)

Guide the students to make it clear that the above three questions are all about buying things with money.

.

The price of each commodity is called the unit price.

How much did you buy?

What is the total price?

.

The unit price in the first question is

five

Angle, quantity is

three

Branch, the total price is

1

Yuan dynasty (1206- 1368)

five

corner

.

The unit price in the second question is

70

Yuan, the quantity is

2

1. The total price is

140

Yuan dynasty (1206- 1368)

.

The unit price in the third question is

nine

Yuan, the quantity is

four

Kilogram, the total price is

36

Yuan dynasty (1206- 1368)

.

for instance

1

As you can see, the relationship between unit price, quantity and total price is:

Unit price × quantity

=

total

Second, speed.

Travel distance

The relationship between time

example

1

Every branch of the car

750

Rice,

four

How long is this branch?

750

×

4=3000(

rice

)

2

Xiao Qiang walks every minute.

66

Rice,

five

How many meters does it take to walk?

66

×

5=330(

rice

)

three

A ship sails every hour.

18

Kilometers,

three

How many kilometers per hour?

18

×

3=54(

kilometre (km)

)

four

The train runs every hour.

120

Kilometers,

2

How many kilometers per hour?

120

×

2=240(

kilometre (km)

)

The above four questions are completed by the students independently, and then the students dictate the process of solving the problems, and the teacher writes on the blackboard.

The teacher instructed the students to observe the above four small problems. What are they talking about? What are their characteristics?

(

The four little questions are all about the same kind of things, all about driving and walking. The characteristic is that the known condition is to walk every minute and every hour.

How many roads, the question is how many roads to take.

)

According to the students' answers,

To sum it up.

The known condition of each of the above questions is every point.

The distance traveled per hour,

We call it.

Speed.

Please summarize what speed is in one sentence.

(

The distance between every minute and every hour is called speed.

)

The teacher definitely added that according to the actual speed of an object, it can be divided into seconds, minutes, hours, days, weeks, months and years.

The distance traveled per unit time is called speed.

(

You can also ask students to give some examples from daily life.

Explain what speed is.

)

Q: So in the title.

four

Points,

five

Points,

three

When,

2

When is it called?

(

The answer is time.

)(

Write on the blackboard.

)

Ask again:

The result of our calculation.

(

That is, the problem in the title

)3000

m,

330

m,

54

Kilometers,

240

Km representative

What is this?

(

The answer is * * * distance.

)

The teacher concluded:

We call a road a distance.

As can be seen from the title, both speed and distance are measured in meters.

Kilometers and other different lengths

Degree unit. Think about the difference between speed and distance. What do you mean?

Speed: the distance traveled by experts in unit time.

Distance: A road traveled by * *.

According to the above four formulas,

Point out the speed,

Time,

The relationship between three distance quantities.

And guide students.

abstract

unlink

Type:

Speed × time

=

Distance.

Tell me about the speed of each question.

What time is it now,

What is the distance?

Then according to the speed × time

=

The relationship between three quantities of distance,

Make up an application question and say what the speed, time and distance are.