Elementary 5 summer vacation homework math problems

Because the surface area is increased by 56 square centimeters compared with the original, only 4 sides are added: 56 4 2 = 7cm is the length of the cuboid, and the height is 7-2 = 5cm, because the height of the cuboid increases by 2cm, it becomes a cube, so its width is also 7cm, and the volume is 7*7*5=245cm

An increase in the height of a cuboid by 2 cm becomes a cube, indicating that the bottom surface of the original cuboid is a square, and the bottom side length is x cmThen the increased surface area is the sum of the areas of the 4 small rectangles added on the 4 sides, and the equation is obtained

2x * 4 = 56

Solve: x = 7

So the height of the original rectangle is: 7-2=5

The volume of the original cuboid: 7*7*5=245 cm3

Solution: If the length of the original cuboid is x, the width is x, and the height is (x-2), then the height of the current cube is x.

According to the title: 6x square - (x square + 2x (x-2)) = 56

Next, you solve the equation yourself.

The height increases by 2 cm, and the area increases by 24 square centimeters, so the bottom side length is 3 cm. Then the original height is 3cm-2cm=1cm, and the original surface area = 3*3*2+3*1*4=30 square centimeters, and the volume after the increase is 3*3*3=27 cubic centimeters.

The bottom edge is 56 4 2=7

Box volume 7*7*5 245

1.The area of a rectangle is 12 square centimeters, and its length and width are all centimeters, how many kinds of such rectangles? What are they?

Answer: There are 3 types of this rectangle, which are 1 12, 2 6, 3 4

2.Write two numbers according to the excitation margin so that their greatest common factor is 1

Both are prime: (2) and (3); Both are composite numbers: (4) and (9); One is a prime number and the other is a composite number: (2) and (9).

3.Of the three numbers, (7) is prime, (7) and (15) are coprimes, (7) is a factor of (21), and the common factor of (15) and (21) is 3

4.The minute hand of a table clock is 8 centimeters long, and after 1 hour, how many centimeters does the tip of this minute hand travel?

5.Two-ninths of a meter is 1 meter (2 9) and is 2 meters (1 9).

6.Four-thirds of the numerators are added with 12, and the denominator should be (expanded by a factor of 5) to keep the size of the fraction constant

7.Two cups of water A and B, of which there is salt in cup A, 20 grams of salt in cup A, and 100 grams of water; There are 30 grams of salt and 200 grams of water in a cup. Which glass of water is saltier?

Cup A: 20 100 = 1 5 Cup B: 30 200 = 3 20

A: The water in cup A is saltier.

1/4+1/2

B barrel of oil = 1 3-1 6

1 6 kg.

A and B two barrels of oil = 1 3 + 1 6

1 2 kg.

Wheat and soybeans are planted in 31 40 of the total area

Corn accounts for 9 40 of the total area

w answer to take oh wwww > three-quarters.

Twenty-three out of twenty.

Seven out of twenty.

Nine out of ten. Twenty-four out of thirty-five.

Seven out of ten. Eighth.

Quarter. Two-fifths.

The latter two are also either w

If you want to ask it, it's very simple, think about it yourself

Three-quarters and nine-tenths of the twenties are too simple, do the math yourself.

It is 20 dm long, 8 dm wide, and 10 dm high.

Surface area: (20 8 + 20 10 + 8 10) 2880 square decimeters = 88000 square centimeters.

A: To make this glass container, you need at least 88,000 square centimeters of glass.

Volume of water: 20 8 4 = 640 cubic decimeters.

8 decimeters. Answer: If it is erected and the minimum surface of the check letter is used as the bottom surface, the water depth is 8 decimeters.

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20 8 2 + 20 10 2 + 10 8 2 = 880 (square centimeters) I don't know if there is a cover, but the seal should not be covered, the first trouble with the second question, the topic of the bend I don't understand, I look at the second question of Zhiji: 20 4 8 (10 8) = 8

Solution: There are x children, Y pieces of candy.

3x+3=y

5x-1=y

The solution yields x=2 y=9

A: There are 2 children and 9 pieces of candy.

Profit and loss issues.

3+1) (5-3) = 2 people.

2*3+3=9 pieces of sugar.

The sum of profit + loss divided by the difference between the two distributions (formula).

There are a few children; (1+3) (5 3) 2 (pcs).

There are two ways to find the sugar number; 1,2 3 3 = 9 (block).

2, 2 5 1 = 9 (block).

Solve with equations: If there are children x people, there will be sugars (3x+3).

5x-1=3x+3

x=2 has 2 children and 9 candies.

There are x people.

3x+3=5x-1

x=23*2+3=9

9 pieces of sugar for two people.

There are x number of children.

3x+3=5x-1

x=2 so there are 2 children.

Sugar has 5*2-1=9 pieces.

It can be solved with equations.

Let the child be x and the sugar be y.

The solution yields y=9, x=2

The number of students in this class is 40, and the number of people who have subscribed to the newspaper is 47.

So 47-40 = people subscribe to two kinds of newspapers.

1.Write words according to their meaning.

1) I was very scared. ( Frightened )

2) Describe the situation as extremely critical (at stake).

3) Forge ahead bravely, regardless of the danger to life. (4) The appearance of the water is magnificent. (Magnificent waves).

It is to calculate the outer skin surface area of the car, if the bottom is also made of aluminum alloy, this is the case, if not, it can be removed.

If you use it all, the calculation formula is: 16*2*(square meters.)

one section with 2* square meters).

354 (sq.m.).

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