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.