Greater than 10.2×2.5

For example, the product of two factors is 75.2, where one factor is 6 times larger and the other factor is 2 times smaller. Are there few products?

The area of the school library is 85 square meters.

The floor is paved with square bricks with a side length of 0.9 meters.

100 is enough?

Example: 4. Calculate (2.4+3.6) × 0.5

What method can you think of?

Example 5: 328- 16

Example 6: Calculate the following problems and check them by multiplication.

15.6 ÷ 12

1.35 ÷ 27

Example 7: Fill in the blanks:

6.23÷0.3=( )÷3

220.5÷ 1.47=( )÷ 147

Example 8: Turn the following problem into division in which the divisor is an integer.

9 1.2÷3.8= ÷38

9 1.2÷3.8= ÷38

5 1.3÷0.27= ÷27

26÷0. 13= ÷

Note: the divisor is a decimal place, and the decimal point of the dividend is moved by the same number of places. When the dividend is not enough, use 0 to make up!

Example 9. Compare with each other

1. Three domestic cows in Zhang Yan produced 220.5 kilograms of milk last week. How many kilograms of milk do three cows produce on average every day?

2. Three cows that zhangyan loves to raise produce 3 1.5 kg of milk a day. How many kilograms is the daily output of each Niu Yi?

The milk yield of the first cow in Zhangyan last Wednesday was 220.5 Jin. How many Jin is the daily output of each Niu Yi?

Example 10. A wire is 3.8 meters long. Wang Lin wants to cut it into pieces of 0.7 meters. How many pieces can he cut at most How many meters of wire are left?

Example 1 1. The rectangle is 8.4 cm long and 4.6 cm wide. What's its circumference?

Centimeter? (Write the formula first, and then substitute the numerical value into the formula for calculation)

There are 36 girls and 24 boys in Class 6 (1). How many people are there in Class One?

(Formula milk powder only)

There is a girl and a boy in Class Six (1), and some * * * has ().

(Write the formula in letters)

Example 13: Which of the following formulas are equations and which are equations? It is the stroke of the equation, and it is the drawing of the equation.

x+3.6 = 7a×2 & lt； 2.4 3- 1.4= 1.6

3÷b8-X = 26.2÷2 & gt； three

4×2.4=9.6 X-2.9=0 2X+3Y=9

Example 14: judge www.xkb 1.com

The formula (1) containing unknowns is called equation ().

(2)4.7x is not equation ()

(3)0.5x=4 is an equation, not an equation ()

(4) As an equation, the formula must be Equation ()

(5) As an equation, the formula must be Equation ()

Example 15: Please use the equation to express the equal relationship between quantities in the following questions.

(1) Xiaohong bought five pens at * * * 9 yuan X Yuan each.

(2) Stationer's table tennis has 40 tubes, X tube has been sold, and there are 18 tubes left.

(3) A place is s kilometers away from B place, and a car travels from A place to B place at a speed of 42 kilometers per hour, 12 hours.

Example 16 A slightly complicated equation application problem:

(1) The children's palace choir has 84 people, three times more than the dance team, 15 people. How many people are there in the dance team?

(2) There are 84 chorus members in the Children's Palace, and the chorus members are eight times less than the dance team. How many people are there in the dance team?

Example 17 A slightly complicated equation application problem:

At the same time, two cars drove out from two stations 237 kilometers apart, and three hours later, the two cars met. One car is 38 kilometers per hour, how many kilometers is the other car?

Can you solve the following equation?

For example,18: 5x+1.5x5 =17.5.

(X-3)2 = 8.5

Example 19: The railway from Tianjin to Jinan is 357 kilometers long. An express train leaves from Tianjin and a local train leaves from Jinan. The two cars are driving in opposite directions. After meeting for three hours, the average speed of the express train is 79 kilometers per hour, and the average speed of the local train is how many kilometers per hour?

Example 20: The store delivered 8 baskets of apples and 0/0 baskets of pears, weighing 430 kilograms. Each basket of pears weighs 23 kilograms. How many kilograms does each basket of apples weigh?

Example 2 1: Two engineering teams * * dug a tunnel with a length of 1 17m. From one end to the other, it will be opened in 13 days. Team A digs 4 meters every day, and how many meters does Team B dig every day?

Example 22: The sum of three numbers A, B and C is 1 160, A is half of B, and B is twice of C. What are these three numbers?

Example 23: The upper bottom of a trapezoid is 9 cm, 3 cm shorter than the lower bottom, and the height is 10 cm. How many square centimeters is its area?

Example 24 True or False Questions

(1) Two trapezoids can be combined into a parallelogram. ( )

(2) Two trapezoids with the same shape can be combined into a parallelogram. ( )

(3) Two identical trapezoids must be able to form a parallelogram. ( )

(4) The area of parallelogram is twice that of trapezoid. ( )

Example 25: Calculate the area below.

Example 26: Xiao Xin cut out a capital English letter "A" with a red self-adhesive paper. What is its area? The first network of new curriculum standards

Example 27: The probability that a dice throws "1" upward is _ _ _ _ _, and the probability of throwing "2" upward is _ _ _ _ _ _ _.

Example 28: If any number is selected from 9 numbers (1-9 * * *), the probability that the selected number is even is ().

Example 29. If someone shoots once and the probability of hitting 0- 10 is equal, then the probability of hitting 8 rings is ().

Example 30: There are 10 cards, which read 1- 10 respectively. How likely is it to draw a card at random and draw 5? What is the possibility of drawing an even number?

Example 3 1: The average value of data 58, 57, 42, 45, 50 and 54 is _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _.

Example 32: Given that the average value of data 1, 2, x, 5 is 2.5, the median value of this set of data is _ _ _ _ _ _ _.

Example 33: Toss two coins at the same time. If a coin is tails, Lee wins, and if both coins are heads or tails, Lee wins. Is this game fair? Explain why. If you throw 100 times, how many times will the two heads appear? The first network of new curriculum standards

Example 34: 15. Two ropes with the same length, the first one is cut in half, and the second one is cut by 0.5m Which length are the remaining two ropes?

Example 35: Liu Jia traveled to Beijing on National Day and brought two white and yellow coats and three blue, black and red trousers. She put on any coat and trousers. How many possibilities are there

Example 36: The average of 8 numbers is 2. 1, the average of the first 3 numbers is 2.6, and the average of the last 4 numbers is 1.4. What's the fourth number?