Elementary school math true false questions. Elementary school math problems?

The volume of a cuboid, a cube, or a cylinder can be calculated using the height of the base area. Two cylinders with equal surface area must have the same volume. If the height of a cylinder is expanded by 2 times, and the base area remains the same, its side area is also expanded by 2 times.

When the height of the cylinder is constant, the radius of the base area is increased by 5 times, and the volume is increased by 25 times. ( Yes ).

Of course, the first question is correct, this is unified, I just finished learning, the second question is wrong, the formula for calculating the volume is not equal to the surface area, the third pair, the fourth is also right.

yes no yes tes heheheI forgot to change the input method。

The score is (18+7) 40=5 8

Multiply the proportion of the scores of the two subjects in the total score (5 8) * 20% = 1 8, and the conversion is a percentage.

The results of the two exams account for the total score.

Both subjects are 20 points, both accounting for 10% of the total score, then the total score is 20 10% = 200 points.

Now the first subject has 18 points, and the second subject has 7 points, which is a total of 18 + 7 = 25 points.

25,200,100% of total grades = 8%.

One pencil case = 3 times the fountain pen.

A pencil case is 12 yuan more than a pen, so much 12 yuan is the pencil case is larger than the pen 2 times, then 1 times is 12 2 = 6 yuan, then the pen's ** is 6 yuan, the pencil case ** is 6 3 = 18 yuan.

The price of a pencil case is 3 times that of a fountain pen, and the pencil case is 12 yuan more than a fountain pen, how much is a pencil case?

Answer: 3x-x=12, a fountain pen is 6 yuan, and a pencil case is 18 yuan.

Fountain pen price: 12 (3-1)=12 2=6 (yuan).

Pencil case price: 6 3 = 18 (yuan).

A: A pencil case costs $18.

The pencil case is 3 times that of the fountain pen, that is to say, the pencil case is twice as much as the fountain pen, since the extra is 12 yuan, then, the average distribution of 12 yuan is six yuan, so the fountain pen should be six yuan. They are listed below.

Answer: The ** of the fountain pen is six yuan.

A pencil case costs 3 times the price of a fountain pen.

The pencil case is 2 times more than the fountain pen.

The pencil case is $12 more than the pen.

So the pen is 12 2 = 6 yuan.

The pencil case is $12 more than the pen.

Pencil case 12 + 6 = 18 yuan.

Suppose the price of the pencil case is y and the price of the fountain pen is x yuan, two equations can be derived from the known conditions: y=3x; y-x=12

From the above equation, we can get: 3x-x=12;

Simplified: 2x=12

Then: x=6 so the ** of the fountain pen is 6 yuan, then the ** of the pencil case is 18 yuan.

If you want to calculate the price of the pencil case, you can first calculate the price of the pen, the price of the pen: 12 (3-1) = 6 (yuan), then the price of the pencil case: 6 3 = 18 (yuan), that is, the price of the pencil case is 18 yuan.

Solution: If a fountain pen is $x, a pencil case is $3x.

3x-x=12

2x=12x=12÷2

x=63x=3 6=18 yuan.

A: A fountain pen is 6 yuan, and a pencil case is 18 yuan.

Pencil case 18 yuan, pen 6 yuan.

Set the fountain pen a yuan, the pencil case is 3a yuan, and then 3a = a + 12, calculate a = 6

Set the pencil case as X and the pen as Y; There are two known conditions for the problem, (1)x=3y, (2)x-y=12;

Bring (1) into (2), you get: 3y-y=12, then y=6, and go back to (1) to get x=3*6=18;

Pencil case = x = 18 yuan.

Fountain pen**: 12 (3-1)=6 (yuan).

Pencil case**: 6x3=18 (yuan).

Let's say the pencil case ** is a pen ** and the pen ** is b

According to the meaning of the question, you can list the formula: a=3b

a-b=12

So there is 3b-b=12, then b=6 yuan, a=18 yuan.

670 years old. If no one is in either group and the average age of all is years, state:

Female member of the badminton group + male member of the table tennis team = male member of the badminton group + female member of the table tennis team

Judging from the question, you should have learned subtraction within 5: then you can fill in the box: 5-5=4-4=3-3=2-2=1-1=0-0=0

The product of two extroverts in a ratio divided by the product of two introverts, the quotient is 1 ( ) two related quantities, either proportional or inversely proportional ( ) 40 degrees south-west that is, 50 degrees south-west ( ) On the map of scale 1:3500000, the length between a and b is measured in centimeters, and the actual distance is 14 kilometers (now converted to units, painted with a distance scale).

If x is divided by 5 = y (y is not equal to 0), then x is proportional to y (think x as the dividend, 5 as the divisor and the dividend divided by the divisor = quotient (y) as the opposite. So yes yes. You don't listen to the lecture at a glance, so I advise you to listen well, and I'm also a sixth-grade student, so you can study hard!