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A math problem with multiple solutions to one problem in the third grade of primary school.
Third grade:

example

1 4

Taiwan Province loom

five

You can knit when you are young.

2600

M, according to this calculation,

24

Taiwan Province loom

15

hour

How many meters can you knit?

Analysis:

This is an application problem of twice normalization,

There is a constant unit quantity in the normalization problem.

In this question,

"At this rate.

Calculate "

Given that the weaving quantity of each loom per hour is constant, it can be used to measure the workload.

Number of units.

Solution 1:

First, divide each loom.

1

Hours of knitting, and then multiply to find out each knitting in turn.

15

small

When the knitting quantity,

24

Taiwan Province loom

15

Weaving quantity per hour:

2600

÷

five

÷

four

×

15

×

24=46800

(meter).

Solution 2:

Find out first

24

Taiwan Province loom

15

The weaving quantity per hour is

four

Taiwan Province loom

five

Several times the amount of knitting per hour:

(

24

÷

four

)×(

15

÷

five

)

= 18

Get to know it again

24

Taiwan Province loom

15

Weaving quantity per hour:

2600

×

18=46800

(meter).

example

2

The original length of the school playground is

60

Meter, width is

50

M, the length has increased after expansion.

20

Increase in meter and width

View from a height or a distance

15

How many square meters has the school playground increased?

Analysis:

Draw a schematic diagram first to help understand the meaning of the question:

Solution 1:

Video courses and learning materials for primary and secondary schools

Video courses, study materials, open classes, and visiting forums with teachers.

As shown in the above picture (1), the blank part in the picture is the original rectangular playground, and the shaded part is the added part. The playground was added after the expansion.

The added area is equal to the area of the expanded new rectangle minus the area of the original rectangle:

(

60

+

20

)×(

50

+

15

)-

60

×

50

=80

×

65

-

3000

=5200

-

3000

=2200

(square meters).

Solution 2:

As shown in the above figure (2),

The shadow part, that is, the added part, can be divided into three small rectangles, and the expanded playground adds faces.

The product is the sum of the areas of these three small rectangles:

15

×

60

+

15

×

20

+

20

×

50

=900

+

300

+

1000

=2200

(square meters).

example

three

A bottle of peanut oil is even heavier than a bottle of peanut oil.

Eight hundred

G, eat half the oil, weigh the bottle together, and there is still some left.

550

Dick.

How many grams of oil are there in the bottle How many grams does this empty bottle weigh?

Analysis:

Solution 1

Depending on the conditions, the weight of peanut oil and bottled oil

Eight hundred

Keru

550

G, because I ate half the oil and half a bottle of oil.

The weight of is

Eight hundred

-

550=250

G, what is the weight of a bottle of oil?

250

×

2=500

G, what is the weight of the oil bottle?

Eight hundred

-

500=300

Dick.

Solution 2:

Depending on the conditions, half a bottle of oil is even heavier than a bottle.

550

G, from

Eight hundred

Subtract half a bottle of oil from the gram.

Eight hundred

-

550=250

g,

550

-

250=300

G is the weight of the bottle, and the weight of the oil is:

Eight hundred

-

300=500

Dick.

Solution 3:

According to "half a bottle of oil with a bottle of * * * weight"

550

G "can calculate the weight of one bottle of oil and two bottles of * * *.

550

×

2= 1 100

G, so bottle weight:

1 100

-

800=300

G, oil weight

Eight hundred

-

300=500

Dick.