Application problem: a square, its side length increases 5 decimeters, area increases 125 square decimeters, seek the area of original square?

Application problem: a square, its side length increases 5 decimeters, area increases 125 square decimeters, seek the area of original square?

5*5=25
125-25=100
100/2=50
50/5=10
10*10=100
The area is 100

How many decimeters is the length of its side? How many decimeters is the area?
Second question:
Fill in the blanks
(1) Division of two numbers is also called two numbers ()
(2) 12:13 can also write (), read (), the ratio is ()
(3) When the truck runs 248km in 4 hours, the ratio of distance to time is ()
(4) A small car consumes (1 / 12) liters of fuel for 1km. According to this calculation, the fuel consumption for (6 / 7) km is () liters
(5) It is estimated that in (2 / 5), (3 / 4), 1.8 and 0.98, (1 / 2) of () is the closest to 1
Third question:
Practical questions
(1) In a formula, the sum of the subtracted, the subtracted and the difference is 480, and the ratio of the subtracted and the difference is 13:11. What is the difference
(2) It takes 10 minutes for Lele to go home from school, and 14 minutes for Lele to go home quietly. It is known that the distance to go home quietly is more than that of Lele (1 / 6). Lele walks 12 meters more per minute than that of Lele, so what is the distance to go home quietly
(3) There are 133 students in a hope primary school, among which girls account for 3 / 7. How many boys are there in this school
(4) The perimeter of the classroom is 288M, and the ratio of length to width is 4:3. How many square meters is the area of the whole classroom
(5) The average weight of Xiaoming, Xiaoli and Xiaoyun is 40kg. Their weight ratio is 5:4:3. How many kg do they weigh
(6) The weight ratio of a and B is 4:1. If 10 g is taken from a bag and put into B bag, the weight ratio of a and B is 7:5, then what is the total weight of two bags of sugar
Fourth question:
Simplification ratio
15km：0.15m 0.75:3 1（3/4）：2（5/8）

How many decimeters is the length of its side? How many decimeters is the area?
The side length of a square is 16 △ 4 = 4 (decimeter). The area is 4 × 4 = 16 (decimeter Square)
Second question:
Fill in the blanks
(1) Division of two numbers is also called the ratio of two numbers
(2) 12:13 can also write (12 / 13 or 12 / 13), read (12:13), and the ratio is (12 / 13)
(3) The truck runs 248km in 4 hours, and the ratio of distance to time is (248:4)
(4) The fuel consumption of a small car for 1km is (1 / 12) liters. According to this calculation, the fuel consumption for (6 / 7) km is (1:1 / 12 = 6 / 7: X,
X = 1 / 14) l
(5) It is estimated that (1 / 2) of (1.8) is closest to 1 in (2 / 5), (3 / 4), 1.8 and 0.98
Third question:
Practical questions
(1) In a formula, the sum of the subtracted, the subtracted and the difference is 480, and the ratio of the subtracted and the difference is 13:11. What is the difference
The subtracted is 480 △ 2 = 240, 13 + 11 = 24, the subtracted is 13 / 24, and the difference is 11 / 24
Difference = 240 × 11 / 24 = 110
(2) It takes 10 minutes for Lele to go home from school, and 14 minutes for Lele to go home quietly. It is known that the distance to go home quietly is more than that of Lele (1 / 6). Lele walks 12 meters more per minute than that of Lele, so what is the distance to go home quietly
Setting: Lele walks XM per minute
Then walk quietly at (X-12) m per minute
14×（X-12）=10X×（1+ 1/6）
14X-168=70/6×X
14X÷6=168
X=72
The distance of quiet walking is 14 × (72-12) = 840 (m)
(3) There are 133 students in a hope primary school, among which girls account for 3 / 7. How many boys are there in this school
133 × (1-3 / 7) = 133 × 4 / 7 = 76 (persons)
(4) The perimeter of the classroom is 288M, and the ratio of length to width is 4:3. How many square meters is the area of the whole classroom
4 + 3 = 7, length 4 / 7, width 3 / 7
Length = 28 ／ 2 × 4 / 7 = 8 (m), width = 28 ／ 2 × 3 / 7 = 6 (m) classroom area = 8 × 6 = 48 (M2)
(5) The average weight of Xiaoming, Xiaoli and Xiaoyun is 40kg. Their weight ratio is 5:4:3. How many kg do they weigh
5 + 4 + 3 = 12, total weight of three persons 40 × 3 = 120 (kg)
Xiaoming accounts for 5 / 12120 × 5 / 12 of the total weight = 50 (kg)
Xiaoli accounts for 4 / 12120 × 4 / 12 of the total weight = 40 (kg)
Xiaoyun accounts for 3 / 12120 × 3 / 12 of the total weight = 30 (kg)
(6) The weight ratio of a and B is 4:1. If 10 g is taken from a bag and put into B bag, the weight ratio of a and B is 7:5, then what is the total weight of two bags of sugar
It turns out that package a accounts for half of the total number of packages
4÷（4＋1）＝4/5
Now, package a accounts for half of the total number of two packages
7÷（7＋5）＝7/12
What's the total weight of two packets of sugar
10÷（4/5－7/12）＝600/13（g）=6/130（kg）
Fourth question:
Simplification ratio
15km：0.15m =1500000:15=100000:1
0.75:3=75:300=1:4
1（3/4）：2（5/8）=7/4:21/8=14:21=2:3