2. There are 22 boys in one class, with an average height of134.8cm; Girls 18, average height 135.2 cm. What is the average height of this class?
3. Xiaohong bought four 5th batteries, paid 8.5 yuan and got back 0. 1 yuan. How much is the fifth battery each?
4. Schools should plant lawns. It was originally planned to plant 27.9 square meters a day and complete the planting in five days, but it actually took only four and a half days to complete the task. How many square meters is it actually planted every day?
5. The school bought five footballs and five volleyballs. It costs 575 yuan to buy football and 360 yuan to buy volleyball. How much is volleyball more expensive than football?
6. Mr. Wang Lin bought a 30-cent science and technology book with 6 yuan money and a 1 minute story book with 5 yuan money. He paid the salesman 15 yuan. How much should I get back? (Calculated in decimal)
7. A clothing factory used to make 3.8-meter uniforms. After changing the cutting method, each set saves 0.2 meters of cloth. Originally made 1800 sets of uniform cloth. How many sets can you make now?
8. Two cars leave from one place in opposite directions at the same time. A car travels 44.5 kilometers per hour on average, and B car travels 6 kilometers less than A car on average. After 3 hours, how many kilometers are the two cars apart?
9. Two cars leave from one place in the same direction at the same time. A car travels 44.5 kilometers per hour on average, and B car travels 60 kilometers per hour on average. After 3 hours, how many kilometers are the two cars apart?
The following is the statistics of donated love in four classes of Grade Four in bright primary school. According to the statistics, answer the following questions:
Quantity item
class
Number of students in the whole grade (person)
Per capita donation (yuan)
total
a ball of
Fifty two
6.8
Class two
48
6.3
Class Three
50
6.08
class four
54
6.6
1, complete the above table. 2. How much does Class Two donate less than Class One?
3. How much does Class Two donate more than Class Three?
4. What is the average donation for each of the four classes?
1, a ton of coal, b tons used every day, how many tons are left after 5 days? The correct formula is ()
① (a-b)×5 ② 5a- b ③ a-5b
2. In a right triangle, the sum of the degrees of two acute angles ()
① Less than 900 ② Equal to 900 ③ More than 900.
3, the comparison of decimal and integer ()
① Decimal is less than integer ② Decimal is greater than integer ③ It cannot be determined.
4. The second counting unit to the right of the decimal point is ()
① Ten places ② One tenth ③ Ten places ④ One tenth.
5. The cyclic part 6.4 164 16 ... is ().
①6 14 ② 4 16 ③ 164
6. The number 4 in the third place to the right of the decimal point means ()
① Four tenths; ② Four percent; ③ Four thousandths.
16, find a rule to fill in the numbers.
19.8 、 18.6 、 17.4 、 。
1. Fill in or remove 0 at the end of a number, and the size of this number remains the same. ( )
2.8×5×7=8×7×5 Apply the multiplicative commutative law. ( )
3, 0.9 and 0.90 have the same size, but the counting units are different. ( )
The product of 4.2.35×8.65 has 4 decimal places. ( )
5. An equilateral triangle belongs to an isosceles triangle. ( )
6. An angle greater than 900 is an obtuse angle. ( )
7. Every angle of a regular triangle is 600 degrees ()
8. The longer the side of an angle, the bigger the angle. ( )
9. Look at 500 with a magnifying glass with a magnification of 2 times. ( )
10, a decimal point. Move the decimal point three places to the left and two places to the right, and the decimal point will be restored to the original110. ( )
1，5， 14，30，55，9 1，x
There are three kinds of cards *** 158. They are arranged in the order of 5 red, 3 white and 4 black. What color is the last card and 140?
Find a pattern and fill in the brackets.
① 1、3、7、() 1 1、 13、()、……
② 1、4、7、 10、()、 16、 19、……
③280、()、200、 160、 120、80、()。
④ 1、2、4、5、7、8、()、()、……
⑤ 1、3、6、 10、 15、()、28、()……
There is an 800-meter-long highway. How many poplar saplings does it take to plant a poplar every 20 meters from beginning to end on one side of the expressway?
Exercise: 1 Set up telephone poles on one side of a 500-meter-long highway, and set up one every 50 meters. If both ends of the expressway are not erected, how many wires are needed?
On both sides of the 50-meter-long runway, a colorful flag is inserted every 5 meters from beginning to end. A * * *, how many colorful flags?
A boulevard in the Red Scarf Park is 800 meters long, and there are 4 1 trash cans at the same distance from beginning to end on its side. How many meters are there between every two trash cans?
1. On one side of a boulevard, 86 telephone poles are fixed from beginning to end. This boulevard is 1700 meters long. How many meters are there between every two telephone poles?
2. A tunnel in downtown park is 200 meters long, and cannas are planted on both sides of the tunnel from beginning to end at equal intervals, with a total of 82 cannas planted. How many meters are there between every two cannas?
There is a begonia tree at one end of a straight Yong road in the street park. Now one begonia tree is planted every 12 meter, and 25 saplings are used. How long is this road?
1. Set a telephone pole every16m on both sides of an expressway, using 52 telephone poles. What is the total length of this highway?
There is a locust tree every 7 meters on both sides of the road. Fangfang took the tram for 3 minutes and saw a pagoda tree on the roadside. 15 1. What is the speed of the tram per minute?
A circular pond is 300 meters in circumference. How many saplings does it take to plant a willow every 5 meters?
Around the circular pool, 40 poplars are planted every 2 meters. What is the circumference of the swimming pool?
A round fish pond is 200 meters long. Now 25 poplars are planted around the pond. How many meters can I plant?
(5), sawing wood
Example 1. There is a piece of wood, and I intend to cut each piece into three sections. It takes five minutes to cut every place. How many minutes does it take to finish sawing?
Practice, 1. There are three pieces of wood, and it takes 3 minutes to saw each piece of wood into 4 pieces. How many minutes does it take to read them all?
2. A carpenter saws a piece of wood with a length of 19 meters. He sawed a broken part 1 m first, then sawed it eight times and sawed it into many short pieces of wood with the same length. How long is each short piece of wood?
It takes 6 minutes for a piece of wood to be sawed into 4 sections, and the same piece of wood is sawed at the same speed. /kloc-How many knots can you saw in 0/8 minutes?
(6) Climb the stairs and ring the doorbell
Example 1: It takes 18 seconds for salesman Xiao Li to climb the first floor. How many seconds does it take him to climb the fourth floor?
Practice, 1. Xiao Li, a salesman, wants to contact the sixth floor. It took him 54 seconds to get from the sixth floor to the fourth floor. According to this calculation, how many seconds does it take for Xiao Li to walk to the sixth floor?
2. The wall clock strikes 6 times at 6 o'clock, and it strikes 10 second. Then knock 9 times at 9 o'clock, knock for a few seconds?
Feedback exercise:
1. Arbor Day is coming. Students plant trees on one side of a path with a length of 120 meters, and plant one every 6 meters.
(1) How many trees does * * * need if there are two kinds of trees at both ends?
(2) How many trees do you need if you only plant one?
(3) How many trees do you need if you don't plant trees at both ends?
2. A circular flower stand with a circumference of 80 meters, with a pot of orchids every 4 meters and a pot of roses every two pots. Q: * * * How many potted flowers do you need?
3. On the anniversary of a factory, colored flags were inserted on both sides of the gate, with a distance of 3 meters between every two colored flags, and 62 colored flags were inserted from beginning to end. How long is this road?
The tree planting team plans to plant a row of trees on both sides of a road with a length of 100 meters. There are 52 trees at both ends of the road. How many meters is the average interval between every two adjacent trees?
5. A rectangular pond is100m long and 40m wide. How many trees need to be planted every 2 meters by the pond?
6. Xiao Gang forms a hollow square with pieces at equal distances, with 16 pieces on each side and one piece at each of the four vertices of the square. How many pieces did Xiao Gang use?
7. The wall clock strikes 5 times at 5 o'clock, and 10 seconds ends. Then, when 12 strikes 12, how many seconds does it end?
It takes six minutes to cut a piece of wood into three sections. If each section is equal in time, how many minutes does it take to cut seven sections?
9. There is a building with a height of 17 floors, and there are 17 steps between two adjacent floors. How many steps does it take for a person to climb from 1 to1?
10.AB raced to climb the stairs. When A ran to the third floor, B happened to run to the second floor. According to this calculation, when A ran to the ninth floor, which floor did B run to?