1, square, rectangle, parallelogram and trapezoid are all special quadrilaterals. (√ )
2. The volume of a cylinder is three times that of a cone, and the base and height of the cone must be equal. (×) didn't say equal bottom and equal height.
3. Proportion is the ratio of the previous paragraph to 1. (x) The ratio should also be 1, which is a reduced ratio.
4. 1 kg metal ratio 1 kg cotton weight. (x) They weigh the same.
5.1100 and 1% are fractions with denominator of 00, and they have the same meaning. (× )
6. The volume of a cone is two thirds smaller than that of a cylinder. (x) is the waiting bottom height.
7. Two rays can form an angle. (× )
8. After a rectangular wooden frame is drawn into a parallelogram, the sum of the internal angles of the four corners remains unchanged. (√ )
9. In any cuboid, only two opposite faces are completely equal. (× )
10, two rectangles with equal perimeters must also have equal areas. ( ×)
1 1, an object with a volume of 1 cubic decimeter must have a bottom area of 1 cubic decimeter. ( ×)
12. The bottom area of a cube with a volume of 1 cubic decimeter must be 1 square decimeter. (√ )
13, the working efficiency is inversely proportional to the working time. (x) It is not said that the total amount of work must be certain.
Original term 14 increased 10%. To keep the proportion unchanged, the latter term should be multiplied by 1. 1. (√ )
15 and 5 kg of salt are dissolved in 100 kg of water, and the salt content of brine is 5%. (x) Use 5÷ 105
16, with large scale and large actual distance. (x) What if it is scaled down?
17. If the perimeter of a square is equal to the perimeter of a circle, the area ratio of the square to the circle is ∏ 7: 4. (x) seems to be π: 2.
18, the smaller the decimal value, the smaller the decimal unit. (√ )
19, 7m 1/8 is as long as 8m 1/7. (x) The front 7/8 meters and the back 8/7 meters are different.
20. Two disjoint straight lines are called parallel lines. (×) Because those two straight lines may not be on the same plane.
2 1, Xiao Wang processed 99 parts, 99 of which were qualified, and the qualified rate of these parts was 99%. (x) Yes 100%
22. Five workers process five parts in five hours, so 1 worker processes 1 part in 0 hours. (10) What if the work efficiency of workers is different?
23. Adding two zeros to the end of a number will enlarge the original number by 100 times. (x) What if this number is a decimal, say 3.24? Add 0 at the end, but the size hasn't changed.
Third, choose:
1, the natural number a divided by the natural number b, and the quotient is 10, then the greatest common divisor of a and b is (b).
a、a B、b C、 10
2. A triangle is divided into two triangles by drawing a line segment through one of its vertices, and the sum of the internal angles of a triangle is (A).
A, 180 b, 90 c, uncertain
3. It takes 10 hour for the bus to drive from A to B, and 15 hour for the truck. The speed ratio between the bus and the truck is (b).
a、2:3 B、3:2 C、2:5
4. When three iron wires with the length of 12 decimeter are enclosed in a rectangle, a square and a circle, the enclosed area (c) is the largest.
A, rectangle b, square c, circle
5. In the division formula m ÷ n = a ... b, (n≠0), the following formula is correct (c).
a、a>n B、n>a C、n>b
6, parallelogram to the opposite side of a vertex can be made (a) high.
A, 1 B, 2 C, countless
7. Use three wires with the same length to form a circle, a square and a rectangle respectively, and (c) has the smallest area.
A, circle b, square c, rectangle
4. Calculation: Please calculate the calculation questions by yourself.
Oral calculation: 2 ÷1%-212.5× 2.5× 0.8× 4
6.3×3/4+3.7÷4/3 (4.5× 1. 1×4.8)÷(3.3×0.8×0.5)
7÷(7-7×0÷7+7÷7) 18×45(5/6+ 1/5)
Subtract the reciprocal of 2.5 from the square of 2, and divide the difference by 120. What is the quotient?
120÷(2? -2/5 )
It's just a formula, not a formula.
The sixth grade students scored 40 points in the school sports meeting, which was 2 times less than that of the fifth grade. How many points did you get in the fifth grade?
(40+24)÷2
Verb (abbreviation of verb) application problem
1. The rectangle is 8 cm long and 4.56 cm wide. What is the area of a circle with the same circumference as this rectangle?
(8+4.56) × 2 = 25.12cm
25.12 ÷ 3.14 ÷ 2 = 4cm.
3. 14×4? =50.24 square centimeters
2. The area of a triangular land is 0.8 hectares, and its bottom is 400 meters. What is its height?
0.8 hectares =8000 square meters
8000× 2 ÷ 400 = 40m
3. A piece of white cloth is a square with a side length of 2 meters, which is cut into an isosceles right triangle with a right angle and a side length of 2 meters. How many pieces can I cut at most?
2 meters =20 decimeters
20÷2= 10 copies
10× 10×2=200 pieces.
4. Use 12.56 decimeter long lead wire to form a square and a circle respectively. How much is the area of a circle larger than that of a square?
12.56÷4=3. 14 decimeter
3. 14×3. 14=9.8596 square decimeter.
12.56 \3. 14 \2 = 2 decimeters
3. 14×2? = 12.56 square decimeter
12.56-9.8596 = 2.7004 square decimeter.
A cylindrical wood is 2 meters long, cut into three equal parts, and its surface area is increased by 24 square centimeters. How many cubic centimeters is the volume of logs?
24÷4=6 square centimeters
2 m =200 cm
6×200= 1200 cubic centimeter
6. The circumference of the bottom of the conical wheat pile is12.56m and the height is1.2m.. If wheat weighs 500 kilograms per cubic meter. How much does this pile of wheat weigh?
12.56 ÷ 3. 14 ÷ 2 = 2m
1/3×3. 14×2? × 1.2× 500 = 25 12kg