1. Divide a 3m-long rope into 4 sections on average, each section accounts for (1) of the total rope length, and each section is (3/4) m long.
2, 72.5 square meters = (7250) square decimeter 2.05 cubic decimeter = (2050) milliliter.
3.5 liters = (3.5) cubic decimeter = (3,500) cubic centimeter.
1500ml = (1500) cubic centimeter = (1.5) cubic decimeter = (0.00 15) cubic meter.
3. Both cuboids and cubes have (6) faces, (12) edges and (8) vertices.
4. Among the 20 numbers of1-20, there are (10) odd numbers and (8) prime numbers, (2) even numbers and prime numbers, and (9 and 15) odd numbers and composite numbers.
5. Use three numbers of 0, 4 and 5 to form a three-digit number, so that it has a factor of 2, a factor of 3 and a factor of 5, the largest of which is (540).
6. Weld a square with 60 decimeters of iron wire, with an area of (225 square decimeters).
7. The two symmetrical axes of a rectangle intersect at the O point. After rotating the rectangle around the O point (180 degrees), it just coincides with the original rectangle.
8. The minute hand of the clock rotates 90 degrees clockwise from "12" to the number "3".
9. The sum of three consecutive even numbers is 24, and these three even numbers are (6), (8) and (10) respectively.
10, the maximum factor of natural number A is 9, and its minimum multiple is (9).
1 1, a cube with a surface area of 54 square centimeters and a volume of (27) cubic centimeters.
12. A bunker is 4m long,1.5m wide and 0.5m deep. This bunker covers an area of 6 square meters and a volume of 3 cubic meters.
13. A conference room is 52 decimeters wide and 36 decimeters wide. Now we need to lay square bricks. The maximum side length of a square tile is (4 decimeters). I * * need such tiles (1 17).
14. The volume of a square with a side length of 3m and a bottom length of 3m is (8 10) cubic decimeter.
Two. Judgment (mark "√" for the right, "×" for the wrong, ***5 points)
1. Rectangles, squares, circles and triangles are all symmetrical figures. (×)
2. Cubes can be regarded as cuboids with equal length, width and height. (√)
It takes at least 4 cubes to spell out a big cube with small cubes of the same size. (√)
4. Natural numbers are either prime numbers or composite numbers. (×)
5. True scores are all less than 1, and false scores are all greater than 1. (×)
Third, choose and fill in the serial number of the correct answer in brackets. (5 points)
1, 5, 10, 15 are all (c).
A, factor b, multiple c, natural number
2. A number is both a factor of 12 and a multiple of 12. This number is (b).
a、3 B、 12 C、24
3. In the formula 15 = 3× 5, 3 and 5 are (c) of 15.
A, prime number b, common factor c, prime factor
4. There are (c) scores greater than 2/9 and less than 4/9.
A, 1 B, 2 C, countless
5. The product of several prime numbers is (b).
A, prime number b, composite number c, even number
Four, as shown below, please rotate 90 clockwise around the O point and draw a triangle ABO, (5 points).
Verb (abbreviation of verb) application questions (5 points for each question, ***45 points)
1. How many square centimeters of wood does it take to make three 30cm-long uncovered cubic wooden cases?
[(30*30)*5]*3
=900*5*3
= 13500 (square centimeter)
Need wood 13500 cm2.
A cuboid wood with a square bottom is 5 meters long. Cut into 4 sections to increase the surface area by 36 square meters. What is the volume of this cuboid wood?
(36/6)*5
=6*5
=30 cubic meters
The volume of this cuboid wood is 30 cubic meters.
3. A 25 cm long cubic oil drum is filled with oil. If the oil weighs 0.4 kilograms per liter, how many kilograms does this barrel weigh?
25 cm =2.5 decimeters
(2.5*2.5*2.5)*0.4
= 15.625*0.4
=6.25 kg
This barrel of oil weighs 6.25 kilograms.
4. A rectangular water tank with a length of 20 cm and a width of 15 cm and a water depth of 6 cm. After placing a cube stone, the water depth is 10 cm. What is the volume of this stone?
20* 15*( 10-6)
=300*4
= 1200 (cubic centimeter)
The volume of this stone is 1200 cubic centimeter.
5. Wooden box with length 1.2m, width 0.8m and height1m.. If it is painted all around the outside, what is the area of the painting?
Around! ! ! ! ! ! Paint them all, so you don't have to paint the top and bottom sides of the wooden box, so
( 1.2* 1 0.8* 1)*2
=2*2
=4 (square meters)
The area of painting is 4 square meters.
6. There is a rectangular steel with a length of 2 meters and a cross section of 5 cm. Each cubic decimeter of steel weighs 7.8 kilograms. How much does this square steel weigh?
2 meters =20 decimeters, 5 centimeters =0.5 decimeters.
0.5*0.5*20*7.8
=5*7.8
=39 kg
This square steel weighs 39 kilograms.
7. There is a fish pond, with a length of 18m, a width of 12m and a depth of 3.5m It is necessary to coat a layer of cement around the fish pond to prevent water seepage. If 5 kilograms of cement is used per square meter, how many kilograms of cement does a * * need?
[ 18* 12 ( 18*3.5 12*3.5)*2]*5
=(2 16 105*2)*5
=(2 16 2 10)*5
=426*5
=2 130 (kg)
A * * * need cement 2 130 kg.
8. Cut a cube with a volume of 64 cubic centimeters from a cuboid with a length of 6 centimeters. What is the original surface area of this cuboid?
The side length of the cube = 4 cm.
So the bottom of the cuboid is a square with a side length of 4 cm and a height of 6 cm, so the surface area of this cuboid is originally
=(4*4 6*4 6*4)*2
=64*2
= 128 (square centimeter)
It turns out that the surface area of this cuboid is 128 square centimeter.
9. A rectangular piece of paper, 48 cm long and 36 cm wide. Cut this paper into square paper with the same size and no excess. What is the longest side of the square?
Find the maximum prime factor of 48 and 36 = 12.
The longest side of a square is 12 cm.
Draw a circle with a circumference of 12.56 cm, and the distance between the two toes of the compass is (2 cm).
Analysis: The distance between the two toes of the compass is the radius, and the radius = 12.56÷3. 14÷2=2 cm.
Draw the largest circle in a square with a circumference of 24 cm. The circumference of this circle is (18.84) cm.
Analysis: A square with a circumference of 24 cm, with a side length of 24÷4=6 cm, a side length of diameter and a circumference of 3. 14× 6 = 18.84 cm.
A line can be a square with a side length of 6.28. If this line is used to form a circle, what is the diameter of the circle
Analysis: The length of the iron wire is exactly the circumference of a circle, and the diameter is = 6.28× 4 ÷ 3.5438+04 = 8 cm.
The circumference of a semicircle is 10.28 cm. What is its radius?
Analysis: the circumference of a semicircle = half the circumference+diameter, that is, 3. 14× radius× 2 ÷ 2+2× radius = 10.28.
Get (3. 14+2)× radius = 10.28, radius =10.28 ÷ (3.14+2) = 2 cm.