(1) The department store shipped 300 pairs of sports shoes in 2 wooden cases and 6 cartons respectively. If two cartons contain the same number of sports shoes in a wooden box, how many pairs of sports shoes are there in each wooden box and each carton?

(2) xinhua primary school buys two tables and five chairs and pays 195 yuan. As we all know, the price of each table is four times that of each chair. How much is each table?

(3) Uncle Wang bought 3kg litchi and 4kg longan, and paid 156 yuan. As we all know, the price of 5 kg litchi is equal to the price of 2 kg longan. How much is litchi and longan per kilogram?

Example 2: Weight of a barrel of oil 180kg. Half the oil is used, and there is still 100 kg in the bucket. Q: How many kilograms do oil and barrels weigh?

Exercise 2

(1) A basket of pears weighs 38kg. Half eaten, there is 20kg left in the basket. Q: How much do pears and baskets weigh?

(2) A basket of apples, weighing 35 kg * * *, first give half to the kindergarten children, then half to the first-grade children, and the rest of the apples weigh 1 1 kg. How much does this basket of apples weigh?

There is some oil in the oil drum. If the oil is doubled, the oil drum will weigh 38 kilograms. If the oil quadruples, the oil and barrels here weigh 46 kilograms. How many kilograms of oil are there in the oil drum?

Example 3: There are five boxes of tea. If you take 200 grams per box, the remaining five boxes of tea are exactly equal to the original four boxes. How many grams are there in each box of tea?

Exercise 3

(1) There are 6 baskets of pears, and the number of pears in each basket is equal. If you take out 40 pears in each basket, the sum of the remaining pears in the six baskets is exactly equal to the original two baskets. How many are there in each basket?

There are as many oranges in five wooden boxes. If 60 oranges are taken out of each wooden box, the sum of the remaining oranges in five wooden boxes is equal to the sum of the oranges in the original two wooden boxes. How many oranges are there in each wooden box?

(1) There are five boxes of biscuits in a grocery store. If 20kg is taken out of each box, the remaining five boxes of biscuits are exactly equal to the original three boxes of biscuits. How many kilograms of biscuits are there in each box?

Exodus 4: A timber factory will produce a number of desks. It was originally planned to produce 60 sheets a day, but in fact, 4 sheets were produced more than originally planned. As a result, the task was completed one day ahead of schedule. How many desks were originally planned to be produced?

Exercise 4

(1) The TV factory has received a batch of production tasks, and plans to produce 90 sets a day, which can be completed on schedule. Actually, five more units were produced every day, and the task was completed 1 day in advance. How many TV sets are there in this batch?

(2) Xiaoming read a story book. He planned to read 12 pages every day, but actually he read 8 more pages every day. As a result, he finished reading it two days in advance. How many pages does this story book have?

(2) To build an expressway, it was originally planned to build 60m a day, but actually it was built15m more than planned every day, resulting in the completion four days ahead of schedule. How many meters did a * * * make?

Example 5: There are two boxes of pushpins, 72 in box A and 48 in box B. How many pushpins should be taken out of box A and put into box B so that the number of pushpins in the two boxes is equal?

Exercise 5

(1) There are two bags of flour, the first bag of flour is 24kg, and the second bag of flour 18kg. How many kilograms are taken from the first bag and put into the second bag, so that the weight of flour in the two bags is equal?

(2) There are two boxes of pushpins, 72 in box A and 48 in box B. How many times do you take out four from box A and put them in box B to make the two boxes equal?

(3) There are two bags of sugar, 68 in one bag and 20 in one bag. How many times can I take six pills from an extra bag and put them in a less bag to make two bags of sugar equal?

The riddle of formula (1)

Thematic analysis:

"Arithmetic puzzle" generally refers to those formulas that contain unknowns or lack operational symbols. To solve this kind of problem, we can use the correct analytical reasoning method to determine the unknowns and symbols in the formula according to the knowledge we have learned. Because the solving process of this kind of problem is similar to guessing riddles, we call this kind of problem "arithmetic problem".

When solving the mystery of the formula, we should carefully examine the questions, analyze the relationship between the data, find a breakthrough, experiment step by step, analyze and solve, and usually adopt backward deduction, rounding method, valuation method and so on.

Example 1: Fill in the appropriate figures in the brackets of the following formula.

7 6 ( ) 5

+ ( ) 4 7

( ) 2 1 ( )

Exercise 1

(1) Fill in the appropriate numbers in the brackets. (2) Fill in the appropriate numbers in the box.

6 ( )( ) □ 0 □ □

+2( ) 1 5 -3( ) 1 7

( )0 9 1 2 8 5 6

(3) In the vertical form below, there are four numbers covered. Find the sum of four numbers in vertical form.

□ □

+ □ □

1 6 9

Example 2: In the following categories, "Giant", "Dragon", "Teng" and "Fei" respectively represent different numbers, and the same Chinese characters represent the same numbers. When each of them represents a number, the following formula holds.

soar

Longtengfei

+Julong Tengfei

2 0 0 1

Exercise 2

(1) C D (2) riddle (3) Macau Gate

Fill in the mysterious door and return

+A B C D+ Ingenious puzzles+YOG door rules

1 9 8 9 1 9 9 5 1 9 9 9

Example 3: Soldiers, guns, horses and soldiers in the following categories each represent one of the ten numbers from 0 to 9, and the same Chinese characters represent the same number. What numbers do these Chinese characters represent?

Soldiers, cannons and horses

+Soldiers and artillery

Exercise 3

(1) Ba A (2) A B C (3) large artillery corps

Bing Ma Bing

+A B B C D Ma Bingbing

C A A

Example 4: seven numbers, 0, 1, 2, 3, 4, 5 and 6, are filled in circles and squares, and each number appears exactly once to form an integer formula.

○×○=□=○÷○

Exercise 4

(1) Fill the seven numbers 0, 1, 3, 5, 6, 8 and 9 in the circle and square basket, and each number appears exactly once to form an integer formula.

○×○=□=○÷○

(2) Fill in 1, 2, 3, 4, 7, 9 to make the equation hold.

□÷□=□÷□

(3) 1, 2, 3, 7 and 8 can be listed as an equation:

( 1+3)×7=28。 Please use the six numbers 0, 1, 2, 3, 4 and 6 to make a formula.

Example 5: Put "+,-,× and \" in appropriate circles respectively (the operation symbol can only be used once), and fill in the appropriate numbers in the boxes to make the following two equations hold.

36○0○ 15= 15 2 1○3○5=□

Exercise 5

(1) Fill in "+,-,×," in the circle below, and fill in the appropriate integer in the box to make the two equations in each group below hold.

① 9○ 13○7= 100 14○2○5=□

② 17○6○2= 100 5○ 14○7=□

(2) Fill the nine numbers 1 ~ 9 in □ (each number can only be used once) to form three equations.

□+□=□ □-□=□ □×□=□

Homework after class:

Mathematics examination paper of the second volume of the third grade

I. Fill in the blanks (2 1)

1.16m2 = () square decimeter 5 hectares = () square meter.

4200 hectares = () square kilometers 4700 square centimeters = () square decimeter.

2. Fill in the appropriate unit name in brackets.

(1) The area of the math exercise book is about 4 ().

China's land area is about 9.6 million ().

(3) My stride is about 30 ().

(4) The classroom door is 2 () high and 2 () in area.

3. Use scores to represent colored parts.

4. There are 28 students in Class Three (1), including girls (12), girls () and boys ().

5. There are 1 white balls, 2 red balls and 3 yellow balls in the box. 1 can be touched at will, and there are () results, with the greatest possibility of touching () ball and the least possibility of touching () ball.

6. The circumference of a square is 24 meters, the side length is () meters and the area is () square meters.

7.250×8, and there are () zeros at the end of the product.

8. Xiaoming is 10 years old. His grandfather is more than six times his age. He is 4 years old and his grandfather is () years old.

Second, the judgment (5 points)

1. The steering wheel of the train moves in translation. ( )

2. The quotient of two digits multiplied by two digits must be four digits. ( )

3. Square is a special rectangle. ( )

A square with equal circumference and a rectangle have equal areas. ( )

5. The perimeter and area of a square with a side length of 4 cm are equal. ( )

Three, choose the correct answer to fill in the brackets (5 points)

The quotient of 1 480÷2÷4 is equal to () of the formula.

A.480℉8° b . 480℉6°c . 480℉5°

2. The height of Xiaojun is 145 ()

decimetre

3. Make a rectangle with two squares with a side length of 3 cm. The circumference of this rectangle is ().

A.24 B.18cm C.12cm

4.4 teams, every two teams have a game. Team * * * competition ().

A. 12

5. A square with a side length of12cm and an area of ().

A.24 cm2 B.36 cm2 C.48 cm2

Four, the calculation part (34 points)

1. Write the results of the following questions directly. (6 points)

5-2.6= 15.8-4.9= 18.3+26.7= 1― =

27×30= 25×8= 120×40= 15.2-4.4=

+ = - = 1 1×5 1= 4000÷5=

2. Use vertical calculation. (10)

42× 19= 354÷6= 64×35= 690÷3= 56×23=

3. Mixed operation. (18)

540÷9÷6 125×3×8 36×7+ 129

860- 13×22 (25+39)× 12 320×(300-294)

Verb (abbreviation of verb) drawing (5 points)

(1) nautical charts should be translated ().

(2) Draw a triangle with five squares on the right on the grid paper.

Six. Application problem (30 points)

1. Lele spent 8.55 yuan on books and a pen. 15 yuan went to 3.2 yuan. How much should I get back?

2. Coke 10 box, water 15 box, 24 bottles per box. How many bottles of drinks are there?

3. How many small squares with an area of 4 square centimeters can be cut out from a square paper with a side length of 16 cm?

4. A building 12 floors, with 8 households on each floor. How many families live in a building like 15?

5. The canteen brought 850 Jin of rice and ate 16, eating an average of 28 Jin a day. How many kilograms of rice are left?

6. The floor of the library is 25mm long and12mm wide. If the library floor is paved with floor tiles with a side length of 2 meters, how many such floor tiles are needed?