5th grade level math problems, find solutions

1.Subtract the volume of the water tank before putting stones from the volume of the water tank after putting stones.

1*m. Convert it yourself.

square decimeters. 3.Time = Volume 20 = 60 * 30 * 2 20 = 180 hours.

Surface area = 2 * (30 * 60 + 30 * 2 + 60 * 2) = 1980 cubic meters.

Length multiplied by width = 60 * 30 = 1800 cubic meters.

1.The volume of the stone is: [(45-36) 100]*1*cubic meter.

cubic decimeters. 3.(1) 60*30*2 20=180 hours.

2) 60*30+60*2*2+30*2*2=2160 square meters.

3) 60*30=1800 square meters.

1.Volume = 100 * 80 * 9 = 72,000 cubic centimeters.

2.Surface area = 2 * (7 * 2 + 7 * 4 + 2 * 4) = 100 cubic decimeters.

3.(1) Time = volume 20 = 60 * 30 * 2 20 = 180 hours.

2) 60*30+60*2*2+30*2*2=2160 square meters.

3) Floor area = length multiplied by width = 60 * 30 = 1800 cubic meters.

Hope it helps.

<> this question, you make up the box and raise your hands early, and it is time for Lu Su to find the answer.

The shadow area in the bottom 3 squares = 1 2x20x10 = 100, and the upper 3 squares in the shadow face laughing wax = 1 2x20x15 = 150

1.Answer: s = (7x2 + 2x4 + 7x4) - 7x2 = 86 square decimeters 2A(1).

60x30+60x2+30x2)x2-60x30=2160 square meters (2).s=60x30=1800 square meters.

3.A: s=(20x15+square meters, n=405 blocks, 4..)A: s=8x5=40 square meters.

1.square decimeters.

2.1014 square decimeters.

3.54 square decimeters.

1. What is the edge length? If it is the length of the square diagonally, laugh at this world, then use paper squares to divide the shirt rice; If it's a side length, it's a square decimeter.

Cube touch limb meters.

1.The fraction with a lower numerator than the denominator is called the simplest fraction. ( False )2A section of the railway was repaired, 12 1 of this section of the railway was repaired in the morning, 12 5 of this section of the railway was repaired in the afternoon, and a total of 2 1 of this section of the railway was repaired in one day. (Right).

Unlike 8 4 fractional units, the magnitude is equal. ( Yes )4A basket of apples, 2 by 2, just enough to finish; I take five of five and can just take it out. This basket of apples must be 10 wrong.

1. Wrong. 2. Right. 12 1 should be written as 1 12, 12 5 should be written as 5 12, 2 1 should be written as 1 2

3. Yes. 4. Not true.

1, the smallest of the four factors is: 6.

2.A number is both a factor of 13 and a factor of 39, and this number is 117. Did you get it?

The first question is, is it a factor of 90, a multiple of 6, or a multiple of 5, and what is that number?

If this number is a multiple of 6 or a multiple of 5, then use 6x5=30And 30 is exactly the factor of 90 (90 = 30x3).

Question 2, my minimum multiple and maximum factor are both 33 What is it?

The maximum factor is 33, and the minimum multiple is 1x, so this number is 33x1=33.

The first question is 30, and the second question is 33

Question 1: 30

I don't understand the second question.。。。

Analysis and answer: Each person planted 8 trees, and there are 14 left, indicating that no one has planted these 14 trees; Each person planted 9 trees, and the last person only planted 6 trees, which means that this person planted 3 trees less, and if there were 3 more trees, each person planted exactly 9 trees; Therefore, 8 trees per person are planted 14 + 3 17 fewer trees than 9 trees per person, and since 8 trees per person are 1 less trees than 9 trees per person, the number of people participating in the tree planting is 17 1 17 people. Specific solution steps:

9-6 3 (trees).

14+3 17 (trees).

9-8 1 (tree).

17 1 17 (person).

A: There are 17 of these students.

Solution: (Faster to solve with binary systems of linear equations).

Set up a total of x students and Y trees.

{8x+14=y

9（x-1）+6=y

Solution: {x=17

y=150

Each person planted 9 trees, and the last person only planted 6 trees, which is 9-6 = 3 trees less.

Thus there are (14+3) (9-1)=17 people.

Let these students have x people, because the number of trees remains the same, so, get:

8x+14=9x-3

Get: x=17

There are x number of these students.

then 8x+14=9x-3

x=17 of the solution

1.What is the volume of a cuboid with a surface area of 16,000 square centimeters, a square on the bottom and a circumference of 160 centimeters?

Analysis: Set the length to x,2A 90-meter-long barrage is trapezoidal in cross-section, with a ceiling of 3 meters at the top and a 14 meters at the bottom, and a height of 4 meters. How many cubic meters of earth and stone are needed to build this barrage?

Solution: The trapezoidal area is: (3+14) 4 2=34 square meters.

The volume of the barrage: 34 90 = 3060 cubic meters of jujube limbs.

3.A rectangular sheet of iron with a width of 20 centimeters, after cutting off squares with sides of 5 centimeters at each of its four corners, was welded into a water tank without a lid. If the volume of the water tank is 750 cubic centimeters, find the length of the iron sheet used for this water tank.

Solution: The length of the water tank is 750 5 (20-2 5) = 15

Then the length of the iron sheet is 15 + 2 5 = 25 cm.

4.Three iron cubes with a surface area of 54 square centimeters, 96 square centimeters, and 150 square centimeters are smelted into a large cuboid (excluding loss) to find the volume of this large cuboid.

Solution: The side lengths of the three small cubes are:

54 6=9 then the side length is 3 cm.

96 6 = 16, then the side length is 4 cm.

150 6 = 25, then the side length is 5 cm.

The sum of the volumes of the three small cubes is 3 3 3 + 4 4 4 + 5 5 5 = 216 square centimeters.

There is no loss of the large cuboid, and the volume remains the same at 216 square centimeters.

5. The bottom surface of a cube is a square, and behind its side is exactly a square with a side length of 12 decimeters, find the volume of the cube.

Solution: The bottom side length is 12 4 = 3 decimeters.

The volume is: 3 3 12 = 108 cubic decimeters.

6.There are 60 tons of water in a rectangular pool, and the pool is 5 meters long and 4 meters wide How many meters is the water deep? (1 cubic meter of water weighs one ton).

Solution: 60 5 4 = 3 meters.

7.How many hours does it take for A to print a manuscript alone, 12 hours for B to type alone, and how many hours does it take for two people to work together?

Solution: 1 (1 8 + 1 12) = hours

3 8 19 5 156 125 23 10 I don't have a score for bands. The most convenient method is to knock on the calculator The pen calculation is more complicated, first turn the sedan chair or into a false fraction, and then reduce the common factor, and turn it into the simplest to know the Dongfan. For example, 375 1000

Again, 4 5 = 19 5