Math 5, math help

Question 1: If B does it alone for x days, it will be changed from: 3 (1 x + 1 18) = 1 4, that is, x = 361-1 4) 1 36 = 27 (days), and it will take 27 days to complete the task.

2 Question Perimeter:

The circumference of the circle so r=50

Area 50 50 square units).

3 questions (1 40 100) (1-5 9) = 4 1532 4 15 = 120 (pages) This book has 120 pages.

4 questions 20384 20000-1=384 20000 100 100

Question 1: Question answer 36, A needs 18 days to do alone, and he has to do 1/18 of that day, 1 6 in three days, and A and 1 4 in three days, so B does 1 12 in three days, and 1 36 in one day, so B takes 36 days to do it by himself

Two topics: Circumference for. 14＊r＊2

You can find r after getting r, and then you can find it.

Three: 32 {1

Four: (20384-20000) 20000*100%.

1.Let the velocity of team B be x, then (1 18+1 x) 3 1 4; x = 363 4 1 36 = 27 days.

2.Perimeter = m r = c 2 = 50 m s = r r = 785 square meters.

3.Let there be a total of x pages x-40%x-5 9 60%x=324Let the interest rate be x 20000 (1+x)=20384

According to the meaning of the question: angle 1 + angle 2 = 90°, 180° - grip angle 1 = 2 * (90 ° - digging angle to judge skin bend 2), the two equations solve the angle 1 = 60 °, angle 2 = 30 °

The sum of consecutive odd numbers is 117, what are these 3 odd numbers? 117 3 = 39 The three odd numbers are .,2. Use the method of decomposing prime factors to find the least common multiple.

a=2*3*3*5 b=2*2*5*7 Then the least common multiple of a and b is 2 2 3 3 5 7 = 1260

x 2+y 2 is seen as (x-0) 2+(y-0) 2

Obviously, the maximum translates to find the maximum radius centered on the origin.

The radius is the largest at point b in the feasible domain.

1) Income in the market** = 18000a - 25*8) + 100]*18 = 18000a - 5400 (RMB).

Income in the orchard** = 18,000 b (RMB)2) Then: Income in the market** = 18,000* -5,400 = 18,000 (RMB).

Income in the orchard = 18,000 * = RMB) = 19,800 (RMB).

In the orchard** this way is better.

Ahem: That's a lot.

1.Let's take the equation that there are x species of birds: 10x+769=90979, so x=9021, so there are now 9,021 species of birds.

2.Calculate 3 20 of body weight: 30x3 20 = 2 9= so not overweight.

3.First of all, the money required for the year before the discount: 10x12=120 yuan After the discount: Yuan Such a month is: 108 12=9 yuan 10-9=1 yuan So a year is less than a month to save 1 yuan.

100 million 60 + 10 = 7 billion The world's population will reach 7 billion in 2013.

5.According to the meaning of the question, it can be obtained: Solution: Let x square bricks be needed 3 times 3 times x x = 2 times 2 times 90 x = 40 so 40 square bricks are needed.

6.Because the ratio of height to bottom diameter is 1:2, and the sum of height to bottom diameter is 9 decimeters, so the height is 9x1 3=3 The bottom diameter is 6 and the bottom radius is 3

So the volume of the cone is cubic decimeters.

7.Let's have a total of x tents The equation is: 20% x+7 20x=4400 x=8000, so there are 8,000 tents in this batch.

8.First calculate that the actual distance is 2000000x6=12000000cm=120km120 80=hours, so it takes hours.

1. In in, natural numbers have ), even numbers have ), odd numbers have ), prime numbers have ), composite numbers have ).

2. After removing the small tree point, it will be enlarged (100) times, and the decimal point of ( will be moved to the right by three places, and then moved to the left by two places is 4

3. Fill in the boxes below with the appropriate numbers so that these numbers are multiples of both factor 2 and factor 3.

28] [Write the equation process].

4. A number has 6 tenths and 4 hundredths, and this number is written as a decimal (, and it is written as a fraction and is (16/25). Write out the process ]

5. Find the law 1/1, 1/9, 1/27, (81) (1) [Write the formula].

6. Write two simplest true fractions (11 70) and (12 70) that are larger than 1/7 and smaller than 1/5 [write process].

7. There are 25% more boys than girls, so there are (20)% fewer girls than boys. Write out the process ]

The numerator of 4/4 is increased by 24, and to keep the size of the fraction unchanged, the denominator should be increased by (30), [Write process. ]

9. If two prime numbers are conceived, the product must be (composite number) [illustrate for example].

10. Divide 1/5 of a ton of rice into 10 equal portions, and each cent accounts for (one-tenth) of the total [equation].

11. The work efficiency continues to improve, and the total amount of work is (proportional) to the working time. [Process].

1、(2，8，20，11，15，1，30） （2，8，20，30） （11，16，1） （11，） 2，8，20，15，30，）

3. (1) 624 There is no calculation process, and it is deduced. Because the multiple of 2 must be even: in a multiple of 3, all the numbers add up to a multiple of 3, such as 624, 6+2+4=12, and 12 is a multiple of 3.

4. ( 16 25) Approximately divided into 27 * 1 3 The previous number multiplied by 1 3 equals the last number 6 11 70 The two numbers are divided.

For example, if a girl is a numerator that increases by a factor of 6, the denominator increases by a factor of 6.

9. Composite number e.g. 5*7

50 equation: 1/5 ten.

11. Proportional.

There are a lot of mistypes, and prime numbers are prime numbers.

By the way, this is a grade exam paper.