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How many minutes is two-thirds of an hour?
60 minutes an hour, 2 / 3 is 60 / 3 * 2 = 40 minutes!
Calculate 11 × 2 + 12 × 3 + 13 × 4 + +198×99+199×100．
The original formula = (11-12) + (12-13) + (13-14) + (198-199) + (199-1100) = 11-12 + 12-13 + 13-14 + 198-199 + 199-1100 = 1-1100 = 99100
If the polynomial (R's Square-1) x's square + (R-1) X-1 about X is a binomial of degree, find R
(R ^ 2-1) x ^ 2 + (R-1) X-1 is a binomial,
And R-1 ≠ 0. R = - 1
The current price of a TV set is 1200 yuan, which is 20% lower than the original price. How much is the original price of this TV set?
1200 + 1200 * 20% = 1200 + 240 = 1440 yuan
The side area of a cylinder is 188.4dm2, and its bottom radius is 2DM. What is its height?
188.4 ÷ (2 × 3.14 × 2) = 188.4 ÷ 12.56 = 15 (decimeter) a: its height is 15 decimeters
How to get the absolute value sign
|How to use this formula
|x-y-1|=2
X-y-1 > 0, the original formula x-y-1 = 2, x-y-3 = 0
x-y-1
If √ 56.7 = a, √ 567 = B, then √ 5.67=____
do somebody a favour
√5.67=√(567×0.01）＝b×0.1＝0.1b
Two fifths of what is eight fifths of what; two ninths of what is eight thirds of what
X x 2/5=8/15
The solution is x = 4 / 3
That is, two fifths of Four Thirds is eight fifths
2/9÷3/8=16/27
That is, two out of nine is 16 out of 27 out of eight out of three
General score: 3AB & # 178; 2% and 2A & # 178; BC: a + B;
The simplest common denominator of 3AB & # 178; and 2A & # 178; BC is 6A & # 178; B & # 178; C
Therefore, 2 / 3 of 3AB and 178 = 4ac / (6a and 178; B and 178; c)
A + B = 3B / (6a & # 178; B & # 178; c)
4.2-1.38 + 5.8-3.62 & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; 16 ÷ [1 ÷ (35-310)] 2 ÷ 23-23 ÷ 2 & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; 35 × 99 + 35
（1）4.2-1.38+5.8-3.62 =（4.2+5.8）-（1.38+3.62），=10-5，=5；（2）16÷[1÷(35-310)]=16÷[1÷310]，=16÷103，=120；（3）2÷23-23÷2 =3-13，=223．（4）35×99+35=（99+1）×35，=100×35，=60．
RELATED INFORMATIONS
- 1. It is proved that LIM (x ^ 2-1) = 3, X tends to - 2 by using ε, δ
- 2. Bivariate linear equation, 4x-3y = 12, what is y when x is 1.2.3
- 3. Find the rule: 12, 0.4, 37.5%, 411514______ ，______ ．
- 4. If the solution of the equation 9x = 17 KX about X is a positive integer, find the value of K
- 5. Xiao Ming does ten math problems. Is there a positive proportion between the problems he has done and the problems he has not done,
- 6. What is the least common multiple of 10,15,18,24
- 7. The sum of all integers whose absolute value is less than 5 is A：7 B：-7 C：0 D：5
- 8. Ask "mathematics class practice and evaluation" seventh grade (1) self-evaluation (5.5
- 9. The price of a coat will be increased by 20% first and then reduced by 20%. Compared with the original price, the price of a coat will be increased by 20%
- 10. The results showed that: 1 / 2:5 / 40.8:1.73 5 / 9:0.2 ratio; 3 5:42 1 / 2:5 / 40.8:1.73 5 / 9:0.2 ratio; 3 5:42 1 / 2:5 / 4 0.8:1.73 5 / 9:0.2 ratio; Reduction ratio What is ratio? Simplify ratio!
- 11. Find the first order partial derivative of the implicit function z = Z (x, y) determined by the equation x / z = lnz / y
- 12. Is a positive definite matrix symmetric?
- 13. A kind of canned beverage developed by an enterprise has two kinds of packaging, large and small. Three large pieces and four small pieces are packed in 120 cans, and two large pieces and three small pieces are packed in 84 cans. How many cans of beverage are packed in each large piece and each small piece?
- 14. Aunt, I buy a box of biscuits, a bag of milk (10 yuan) children, originally you use 10 yuan to buy a box of biscuits is much But it's not enough to buy another bag of milk! Today is children's day. I'll give you 10% discount on the biscuits I bought. Please take two things. There's also your change of 80 cents. The price of a box of biscuits is in integer yuan. (please use one yuan equation to solve it, thank you.)
- 15. The little boy said, "Auntie, I'll buy a box of biscuits and a bag of milk." then she handed me 10 yuan. Auntie said, "little friend, I bought a box of biscuits Biscuits are enough, but it's not enough to buy another bag of milk. Today is January 1, 2007. I'll give you a 10% discount on the biscuits I bought. Please take care of the two things and your change of 80 cents. "The little girl said," a box of biscuits is 7% more expensive than a bag of milk. " How much is a box of biscuits and a bag of milk? Also, it's better to use the equation to solve it Forget to say, with the equation of degree one variable
- 16. When a craft is sold at the marked price, it will make a profit of 45 yuan per piece. When 8 pieces of the craft are sold at 50% off the marked price, the profit is equal to 12 pieces of the craft when the marked price is reduced by 35 yuan? 2. A and B depart from city a and go to city B respectively. A returns to city a to pick up things on the way, but does not stop to go to city B. they arrive at city B at the same time. If the time starts from two people's departure at the same time, they will arrive at the same time in 35 minutes. It is known that a's journey per minute is 39 meters less than that of B's? 3. A shop purchased a batch of lamps, each of which costs 13 yuan. 12 lamps were damaged during transportation. The unit price was 15 yuan when they were sold, and a total profit of 1020 yuan after they were sold out. How many lamps did you buy?
- 17. A rectangular reservoir is 2m long, 1m wide and 2m long. How many cubic meters can the reservoir store water? How many meters should the reservoir be raised to store 3 cubic meters?
- 18. As shown in the figure, OC is the bisector of ∠ AOD, OE is the bisector of ∠ BOD. If ∠ AOB = 130 °, what is the degree of ∠ COE?
- 19. A classmate has to arrive at the place B 15 kilometers away from the place a in four hours. After he started from the place a, he walked at the speed of 3 kilometers per hour for one hour. After that, at least how many kilometers per hour do he have to walk to reach the place B as planned? 2. Put less than 40 chickens into several cages. If there are 4 chickens in each cage, there will be 1 chicken without cage. If there are 5 chickens in each cage, there will be 1 chicken without cage, and the last cage is less than 3. How many cages are there? How many chickens are there? 3. An engineering team originally planned to excavate at least 600 cubic meters of soil in 10 days. In the first two days, it completed 50 cubic meters of soil every day. Due to the adjustment of the construction period of the whole project, it is required to complete the excavation task three days in advance. How many cubic meters of soil will be excavated in the next few days?
- 20. Fill in the blanks: 1. The area of two rectangles is equal. It is known that the ratio of the length of the two rectangles is 8:5, and the ratio of their width is () 2. Add 6 grams of salt and 14 grams of water to the salt water with 30% salt content, then the salt content in the new salt water is () 3. For a commodity, the price has been reduced by 10% for two consecutive times, and the current price is equal to () of the original price 4. When preparing peracetic acid disinfectant, it should be prepared according to the mass ratio of 1:200. Now the personnel have put 0.3KG peracetic acid into 50kg water. If the disinfectant meets the requirements, it should be () Practical questions: 1. A basket of fruit weighs 50 kg in total. After selling 50% of the fruit, the basket weighs 27 kg in total. How many kg does the fruit weigh? 2. If a commodity is reduced by 10% of its current price, it will still make a profit of 200 yuan; if it is reduced by 20%, it will lose 220 yuan. What is the current price of this commodity? 3. A 60 kilometer long highway is divided into three sections: uphill, flat and downhill. The length ratio of each section is 1:2:3. Uncle Zhang's riding time is 3:4:5. It is known that his riding speed on flat road is 25 kilometers per hour. How long does it take him to complete the whole journey? 4. Zhongshang supermarket is engaged in promotion activities. For those who purchase goods with a value of more than 200 yuan, they can draw a lottery ticket with a total of 2000 tickets until they are finished. There are 20 mid-term first prizes with a value of 800 yuan, 30 second prizes with a value of 500 yuan, and 100 third prizes with a value of 100 yuan. What is the winning rate of this promotion? If all the lottery tickets are drawn, how many yuan of goods have been sold at least, What is the maximum percentage of sales? All practical problems need to be solved by formulas!