Who can give me some additional questions about mathematics,

1. A barrel of oil, the first pour 40%, the second less than the first pour 10 kg, the barrel is still 30 kg of oil, the barrel of oil originally how many kg? 2, a total of RMB several yuan, including a 60% of the total amount of money, if B to a 120 yuan, then B the remaining money accounted for 25% of the total amount of money, a how much money? 3, the existing

There is a pile of go pieces, in which the ratio of the number of black and white pieces is 4:3. Take 91 pieces out of them, and the ratio of the number of black and white pieces is 8:5, while the ratio of the number of black and white pieces in the remaining pieces is 3:4. So how many go pieces are there in this pile?

The number of sunspots taken is 91 × 88 + 5 = 56, and the number of white ones taken is 91-56 = 35. If the original number of sunspots and white ones are regarded as 4x and 3x respectively, there are (4x-56): (3x-35) = 3:4, & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp

1. Team a and team B dig a canal. It takes 24 days for team a to dig alone and 30 days for team B to dig alone. After several days of simultaneous digging, team a will finish the rest in 6 days. How many days did Team B dig?
2. For a project, team a can complete it in 20 days and team B can complete it in 30 days. After several days of cooperation between the two teams, the rest will be completed by team a alone. From the beginning to the completion of the task, team a worked for 16 days. How many days does team B work?
3. It takes 12 hours for a bus to go from station a to station B, and 15 hours for a freight car to go from station B to station a. the two cars leave each other at the same time. When they meet, the bus is 320 kilometers away from station B. how many kilometers are there between the two stations?
4. It takes 12 days for Party A to do it alone, and 15 days for Party B to do it alone. Party a works for 3 days, and then Party A and Party B work together. How many days does this work take from the beginning to the end?
5. Party A and Party B work together to complete 1 / 12 of all the work every day. Party a works alone for 6 days, and Party B works alone for 10 days, leaving 11 / 30 of all the work unfinished. How many days does it take for Party A to complete all the work alone?
6. In a project, two fifths of the total length of a highway was built on the first day, three tenth and twenty-four meters of the remaining part was built on the second day, and three fourths and sixty meters of the first day were built on the third day, which happened to be completed. How many meters is the total length of this highway?
7. The number of heads of cattle is 1 / 4 more than that of sheep, and how many points less than that of cattle?

1.13 days
2.10 days
3.720 M
4.8 days
5.20 days
6.700 M
7. One fifth
My first year of junior high school

The denominator of a fraction is 901, and the numerator is a prime number. There are two ways. One is to add the numerator and denominator to the same one digit number at the same time, and the other is to subtract one digit number at the same time. One of the ways is to form a new fraction. After the new fraction is reduced to 7 / 13, the original fraction can be obtained
Each of the seven plates numbered 1 to 7 has 80 glass balls, of which 18 are placed in plate 1, and the sum of the glass numbers of the three plates numbered adjacent to each other is equal. How many glass balls are there in plate 6?
All of them are from grade six. We should make a list and explain them. Don't be so complicated, or the teacher won't believe it

Let 901 + 9 = 910910910 * 7 / 13 = 490, then the original molecule is 481, but 481 is not a prime number and can be divisible by 13. Then the next hypothetical number is 897 (because it needs to be divisible by 13). Calculate 487, which is a prime number

How to write the additional questions in the sixth grade mathematics test paper (7)
People who know write down the process, online and so on!
Yes, 1 A, B and C go to save money. It's known that the average amount of money saved by the three people is 2000 yuan. The ratio of the amount of money saved by family a and B is 3:2. The amount of money saved by C is 400 yuan less than that of A. how much money are the three people in each village?
2. It takes 5.5 hours for the postman to walk from a to B. due to the rain, there is a muddy road of 3.6 kilometers in the middle. The speed of this section of road is only three-quarters of the original speed. Therefore, how many kilometers is it from a to B 12 minutes later than the original?

2000 times the sum of 3 and 2 = 400
400 times 2 = 800
400 times 3 = 1200.1200-400 = 800 800-400 = 400
A 1200 B 800 C 400

40% of a number is 8.5 less than 50%. What's the number
We should synthesize the formula.

Formula? If it's an equation, it's convenient
8.5÷（50%-40%）
=8.5÷0.1
=8.5*10
=85

Sixth grade mathematics exercises (to have analytical)
Urgent, it will be used the day after tomorrow
To the second unit of the sixth grade, find the volume of cylinder and cone

A cylinder has a radius of 2 square decimeters and a height of 4.5 square decimeters
3.14 * 2 * 2 * 4.5 + 3.14 * 2 * 2 * 2 = 81.64 (square decimeter)
Analysis:
Calculate the lateral area
3.14 * (2 * 2) * 4.5 = 56.52 (square decimeter)
Find two base areas
3.14 * (2 * 2) * 2 = 25.12 (square decimeter)
Calculate the surface area
56.52 + 25.12 = 81.64 (square decimeter)

1. Solve the following equation
（1）（x+y=-2
（x+z=13
（y+z=1
（2）（x-y-z=-1
（3x+5y+7z=11
（4x-y+2z=-1
Write the steps and conclusions,

X = - y-2z = 1-y according to x + Z = 13, we get - Y-2 + 1-y = 13-2y = 14y = - 7x = 5Z = 8x-y-z = - 1, formula 1 * 3 gets 3x-3y-3z = - 3, formula 2 3x + 5Y + 7z = 11, formula 2 minus 3, formula 8y + 10z = 14, y = (14-10z) / 84x-y + 2Z = - 1, formula 1 minus 4 gets - 3x-3z = 0, we get x = - Z, substitute y = (14-10z) / 8 and x = - Z into formula 3

With the replacement method, the school will pay 960 yuan for 8 basketball and 10 volleyball. The money for 7 volleyball can buy 4 basketball. How much is each volleyball?
Write down the specific process

If a volleyball is x, a basketball is 7-4x
8*7\4X+10X=960
24X=960
X=40
Answer: each volleyball is 40 yuan

Answers to the questions on page 14-15 of the first volume of mathematics in primary school

P22: 12-4 = 8 (decimeter) 10-4 = 6 (decimeter) 8 * 6 * 2 = 96 (liter) P25: 5 * 5 * 6 = 150 (square decimeter) I don't have a book. Put the title aside and you should write it down

Who can give me some additional questions about mathematics,