1, 6045809090 is pronounced as (six billion four hundred and fifty thousand Wu Bai eight hundred and ninety), and the approximate number rounded to ten thousand places is (60458 1) ten thousand.
The decimal units of 2 and 5 are (units). If the decimal unit such as (1) is removed, it will become the smallest composite number.
Of the four figures of 3.0.6, 66% and 0.666, the largest is (0.666) and the smallest is (0.6).
4. Of the nine numbers1to 9, two adjacent numbers are prime numbers (5) and (7), and two adjacent numbers are composite numbers (4) and (6).
5.A number = 2× 3× 5, B number = 2× 5× 7, the greatest common divisor of A number and B number is (5), and the least common multiple is (2 10).
6. Prepare a brine with the weight ratio of salt to water of 1:2, and the salt is the weight of brine (1/3).
7. Put two squares with a side length of 5 cm into a rectangle with a circumference of (30); The area is (50).
8. The surface area of a cube with a side length of 6 cm is (2 16). The volume is (2 16).
9. In A ÷ B = 5 ... 3, A and B are expanded three times at the same time, the quotient is (5), and the remainder is (3).
Second, the judgment, the correct "tick", the wrong "x". (6 points)
1, it is easier to see the change of quantity and energy in broken-line statistical chart. (right)
2. The former term of the ratio is multiplied by 2, and the latter term of the ratio is divided by 2, and the ratio remains unchanged. (error)
3.Decimal is a number less than 1. (error)
4. Two even numbers are definitely not prime numbers. (right)
5. The equation is an equation, but the equation is not necessarily an equation. (right)
6. The quotient of 1 .3 divided by 0.3 is 4 and the remainder is1. (error)
Third, choose the serial number of the correct answer in (). (12)
1, the wheel rolls once, and the distance traveled is to find the wheel (②).
① Diameter ② Perimeter ③ Area
2. When calculating the volume and volume of rectangular wooden cases, (3) is the same.
① Calculation formula ② Significance ③ Measurement method
3. The prime factor of decomposing 60 is 60 = (②).
① 1×2×2×3×5 ②2×2×3×5 ③3×4×5
4. If number A and number B are not equal to 0, then number A is1/3 >; 0/3 of 65438+B, then (①).
① A number > B number ② B number > A number ③ A number = B number
5. The length of a steel pipe is15m, and 1/3 of the total length is cut off. According to the formula 15× (1- 1/3), the problem is (②).
(1) How many meters are cut off? ② How many meters are left?
(3) How many meters more than the rest? (4) How many meters are left over from the cut?
6. For a batch of corn seeds, the ratio of germinated grains to ungerminated grains is 4: 1, and the germination rate of these seeds is (②).
①20% ②75% ③25% ④80%
Fourth, the calculation problem. (3 1)
1, a number written directly. (6 points)
25×24=600 4.2÷0.2=2 1 12-2= 10
1.25×8= 10 1÷0.6=5/3 4÷2=2
2. Use a simple method to calculate. (6 points) 1
①3.5%×9.9=3.465 ②4.62+9.9= 14.52 ③4×0.6+0.6÷4=2.25
3. Off-mold calculation. (12)
①2700×(506-499)÷900 ②33.02-( 148.4-90.85)÷2.5
=2700×7÷900 =33.02-57.55÷2.5
= 18900÷900 =33.02-23.02
=2 1 = 10
③( 1÷ 1- 1)÷5. 1 ④ 18. 1+(3-0.299÷0.23)× 1
=( 1- 1)÷5. 1 = 18. 1+ 1.7x 1
=0÷5. 1 = 18. 1+ 1.7
=0 = 19.8
4. Solve the equation. (4 points)
① 5x+ 15x=400
Solution: 20X=400
X=20
5. Column calculation. (6 points)
1, 0.4 less than 20% of a certain number is 7.2. Find a number. (Equation solving)
20%x-0.4=7.2
What is the sum of the difference between 2.0.9 and 0.2 plus 1 divided by l.25?
0.9-0.2+ 1.25÷ 1
6. The circumference of the circle below is 25. 12 cm. Find the area of the graph. (5 points)
25. 12÷3. 14÷2 4×4×3. 14
=8÷2 = 16×3. 14
= 4cm = 50.24cm2.
Seven, application questions. (35 points)
1. The construction team dug a canal. It was originally planned to dig 100m every day, and it was completed in 24 days, but it was actually completed 4 days ahead of schedule. How many meters does it actually dig every day?
100×24÷(24-4)
=2400÷20
= 120 (m)
2. A car traveled from A to B three hours ago 156 km. At this speed, it takes 8 hours to get from A to B. How many kilometers is there between A and B? (Use proportional solution)
156/3 :x/8
Solution: 3 x= 156×8
X=4 16
3. There are two ribbons, the first one is 6.2 meters long, and the second one is 0.2 meters shorter than the second one. How many meters are the two ribbons?
6.2+(6.2×2-0.2)
=6.2+ 12.2
= 18.4 (m)
4. A school uniform 54 yuan, in which the price of trousers is 4/5 of that of coat. What are the prices of coat and trousers?
X+4/5 X=54
9/5 X=54
X=30
30×4/5=24
5. To build a road, it takes four days for the first construction team and six days for the second construction team. If the two teams repair together, how many days can the road be completed?
1÷( 1/4+ 1/6)
= 1÷5/ 12
=2.4 (days)
6. On the map with the scale of1:4,000,000, the distance between A and B is 20 cm, and two trains start from A and B at the same time. The speed of A train is 55 kilometers per hour and that of B train is 45 kilometers per hour. They will meet in a few hours.
20/x: 1/4000000 8000000 cm =800 km
1x = 20×400000800(55+45)
X=80000000 =8 (hours)
7. A conical rice pile, with a bottom radius of 1 m and a height of 1.5 m, weighs about 600 kg per cubic meter of rice. How many kilograms does this study pile weigh?
1× 1×3. 14× 1.5× 1/3×600
=3. 14× 1.5× 1/3×600
=4.7 1× 1/3×600
= 1.57×600
=942 (kg)