Mathematics 6th grade questions, the master comes to !!

A short 4 centimeter is the two radii of a circle. So the radius is 4 2 = 2 cm.

The circumference of the circle is 2*2*cm.

The area of the circle is a square centimeter.

The extra 4cm is the diameter of the circle, and the circumference of the circle is 4* The area is the same.

Olympiad teacher help you:

Divide a circle into several equal parts and convert it into a rectangle, then the circumference of this rectangle should be: 2 r+2r, and the circumference of the circle is 2 r, so r=2, that is, the circumference is 2 r=cm, and the area is square centimeters.

If a circle is divided into several equal parts and converted into a rectangle, then the circumference of this rectangle should be: 2 r+2r, and the circumference of the circle is 2 r, so r=2, that is, the circumference is 2 r=cm, and the area is square centimeters.

If A does it alone for 2 hours and B does it alone for another 2 hours, then two people will complete it.

So B can do engineering for another 1 hour alone.

1 (1 12) = 12 (days).

A: It takes 12 days for B to complete alone.

It takes x days for B to be completed alone, and the total project is 1Then 1 x is B's work efficiency, then 13 36 3 x is A's work for 2 hours, divided by 2 is A's work efficiency, then A's work efficiency plus B's work efficiency = 5 36, you can find the value of x as 12

Analysis: Divide the circle into several (even) equal parts and put together an approximate rectangle, the length of the rectangle is half of the circumference of the circle, and the width of the rectangle is the radius of the circle. Because the area of the rectangle = length and width, the area of the circle = radius radius = r r = r

Process you can hi me.

1. False. 2. False, if all are qualified, the pass rate is 100%.

3. Wrong, the quality of the brine is 105, so the salt accounts for the brine.

4, right.

1. Wrong because the unit cannot be added after the percentage.

2. The pass rate is 100, so it is also wrong.

3. Do the math yourself if dividing 5 by 105 is 5 percent.

4. That's right.

Judge right from wrong. 1. A one-meter-long rope has used 30% of the remaining 70% of the meters. (False) 2. Master Li processed 90 parts, all of which were qualified, and the pass rate was 90%.

3. Dissolve 5 grams of salt in 100 grams of water, and salt accounts for 5% of the brine. 4. Divide the five-meter-long iron wire into 10 equal parts, each accounting for 10% of it. Right).

The B number is one-fifth of the A number.

Number B = 1 5 Number A.

The number C is one-fifth more than the number of A.

C number = (1 + 1 5) A number = 6 5 A number.

The number of Ding is one-fifth less than the number of A.

Ding number = (1-1 5) A number = 4 5 A number.

A, 5, B, 5, 6C, D.

What is the process of this ...

If you don't, just set a value for A.

For example, A5B, 1C, 6D, 4

B: 1 5A.

C: (1+1 5) A = 6 5 A.

D: (1-1 5) A = 4 5 A.

The first question is 3 common factors;

First of all, A = B + 4 = C + 8 So C is equal to (48-4-8) 3 = 12, so B is 16, A is 20, so the greatest common factor is 4, and the least common multiple is 3*4*5*4=240 In fact, because A is 4 larger than B, and B is 4 larger than C, so it is obvious that the greatest common factor is 4, and there is no need to calculate.

In the second question, because the greatest common factor is 24, this number may be 24*1 and 24*3, that is, 24 and 72

The third question: 66 = 6 * 11 70 = 7 * 10 102 = 2 * 51 110 = 11 * 10 255 = 5 * 51 105 = 5 * 3 * 7

Obviously, two of the same factors are separated, so.

I don't want your high score, but I hope you can learn knowledge seriously instead of using your cleverness to complete tasks.

1.C = (48-4-(4+4)) 3 = 12 B = 12 + 4 = 16 A = 20

The greatest common factor is 4

The least common multiple is 4*3*4*5=240

1. C = (48-4-8) 3 = 12;B = 16;A 24=2;24*3=72；24*4=96；24*5=120 (untitled), 72

First of all, the water inlet pipe should be pumped in several bark empty shed pumping pipes for the water phase combustion per hour

21x8-24x6) (8-6) (168-144) 2 24 2 12 (root).

Then find that the water in the original pool is equivalent to the loss of several pumping pipes

24-12) x6 12x6 72 (root).

72 (16-12) 72 4 18 (hours).

Set up 1 slag beam water pipe to drain 1 unit of spring collapse water in 1 hour.

8-6=12 means 12 units of water per hour.

The original water is 24*6-12*6=72

Because 12 units of water are fed into each small beam round.

Let 12 pumps pump the water that comes in and the rest of the water that comes in.

Add a few points.

: 7 proportional dividends, so the dividends of the two are 4 11 and 7 11, the difference between the two is 3 11, A is less than 2400 yuan, so the bonus is set up for a total of x yuan, 3x 11 = 2400, and the solution is x = 8800 yuan, so A's dividend = 4 11 * 8800 = 3200 yuan, and B's dividend = 7 11 * 8800 = 5600 yuan.

2. The mass of sugar in the original sugar water = 5% * 100 = 5 grams, then the water is 95 grams, and after adding sugar, it is 5 + 25 = 30 grams, so the sugar content in the sugar water = 30 (95 + 30) = 24%.

3. There is a title to know, the second and third total volume = 72 (3 5) = 120 tons, these two times the volume is 60%, so the total amount of goods = 120 60% = 200 tons.