Primary 4 math problems explained, what are the 4th grade math problems?

Arithmetic methods solve problems.

Analysis: Assuming that these 82 are all chickens, then there are 164 legs, and they do not meet one of the conditions in the problem, and there are 90 feet less, which must be because the rabbit is also counted as a chicken, so replace a chicken with a rabbit, add 2 legs in the middle, and divide 90 by dividing it to get the number of rabbits, and it will not be too difficult to ask for chickens.

Answer: (254-82 2) (4-2) = (254-164) 2 = 45 (rabbits) * number of rabbits.

82-45 = 37 * number of chickens.

Equation approach to problem solving.

Analysis: We can assume that the number of chickens or rabbits is x, then the number of rabbits is 82-x, and there are several modules below, choose at will.

Module 1: 2x+4 (82-x)=254

Module 2: 2x=254-4 (82-x).

Module 3: 254-2x=4 (82-x).

I chose module 1 as an example to calculate.

Answer: The number of chickens is x

2x+4×(82-x)=254

2x+328-4x=254

328-2x=254

2x=328-254

2x=74x=37

82-37=45 (only).

Solution: Let the number of chickens be x

2x+4×(82-x)=254

Solution: x=37

The number of rabbits is: 82-37=45 (only).

Chickens and rabbits in the same cage.

Let 82 chickens have feet, 82 * 2 = 164 more 254-164 = 90 feet, that is, rabbits, find the number of rabbits 90 (4-2) = 45 (4-2) is the number of feet per rabbit than each chicken.

Chickens: (254-45*4) 2=37 chickens.

Got it! ~~

254 2-82 Getting a Rabbit Explanation: Removing half of the chicken's and rabbit's feet and removing another of their feet Leaving only one rabbit's foot!

82 And then subtract the number and it will be a chicken!

The math problems in life for 4th grade are as follows:1. The problem of baking cakes: it takes two minutes for my mother to bake a cake, one minute for each of the front and back sides, and a maximum of two cakes in the pot at the same time.

2. Socks problem, there are 5 pairs of socks of different colors in the drawer, and the lights are not turned on, so how many socks of the same color need to be found out at most? Misconduct.

3. Table problem, a square table, cut off a corner and how many corners?

4. Tofu cutting problem: How many pieces can you cut into three pieces of tofu?

5. Cutting watermelon problem: cut 7 cloves with three knives, and there are 8 pieces of skin left after eating, how to cut them?

6. Bamboo pole question: Can a 5-meter-long bamboo pole pass through a one-meter-high door?

7. Carton problem: Can a square box with a side length of one meter put down a wooden stick of rice?

8. Clock question: 12 hours, how many times do the clock and minute hand repeat?

If you plant a tree, there are two 3 meters between the two teaching buildings, and if there are two trees in the middle, there are 3 3 meters between the two teaching buildings, and so on, 25 trees indicate that there are 26 3 meters between the two teaching buildings, and the distance is 26*3=78 meters.

This question examines the application of mixed operations;

According to the title,"The area of planted cypress saplings is one of the area of a square nursery.

Half less than 20 square meters"Equivalent to"The area of cypress saplings is increased by 20 square meters.

It is half the area of a square nursery", the area of pine saplings planted is 120

square meters, drawing the diagram shows that half of the nursery is pine seedlings minus.

20 square meters, so half of the area of this plot is: 120-20).

square meters , one half times two of the area of the land is the sum of the land .

area, i.e. .

200 (m2)

Question 4?

Set cypress saplings with an area of x square meters.

Cypress sapling area = total area 2-20

Total area = 2 * (cypress sapling area + 20) = 2 * cypress sapling area + 40 total area = pine sapling area + cypress sapling area.

2 * cypress sapling area + 40 = pine sapling area + cypress sapling area i.e. 2x + 40 = 120 + x

x=80

Total area = 120 + x = 120 + 80 = 200 (square meters) 80 200 = 2 5

It should be divided at squares 2 5 in the figure.

Divide the square into 10 equal parts like this.

The area of the cypress + 20 times 2 is equal to the area of the cypress + pine, which is also equal to the area of the nursery.

The title says Ha (灬 灬).

Ri planned Guanghe Li San Lane he was in a hurry to reform the six six six carat lovers institutional reform he actually came to see snipe Tari Cusack.

There are 368 pages left unread.

At this rate, it would take Kobayashi about 4 days to finish reading this storybook.

The following questions are all okay.

I suggest you do it yourself

Problem solving.

1. The canteen has transported 600 kilograms of rice, 240 kilograms have been eaten, and the remaining rice has just been eaten in 9 days, how many kilograms are eaten per day on average?

2. There are 4 rows of pear trees in the orchard, 28 trees in each row, and the total number of pear trees is 21 fewer than that of peach trees. How many peach trees are there in the orchard?

3. The engineering team installs a batch of electric poles. Pack 18 pieces a day, and it can be completed in 30 days.

1) If it takes 20 days to complete, how many should you install per day?

2) If you load 36 sticks a day, how many days can it be completed?

4. A tree is planted every 5 meters on one side of the road, and there are 71 trees at both ends. How many meters is the road?

5. Three groups produce parts, the first group produces 198 pieces, the second group produces 202 parts, the third group produces 14 pieces less than the sum of the first and second groups, and the third group produces a few pieces?

6. The fertilizer plant wants to produce 5,200 tons of fertilizer, which has been in production for 25 days, producing 120 tons per day. The rest should be completed in 8 days, how many tons will be produced per day on average?

7. A car travels an average of 78 kilometers per hour, and a train travels 3 kilometers in 3 hours more than the car travels in 5 hours. How many kilometers does this train travel on average per hour?

8. Xiao Wang drove from City A to City B, which was 420 kilometers away, traveling 80 kilometers per hour. 3 hours later I was notified that I had to arrive at City B within 2 hours. Can Xiao Wang reach City B on time at the original speed?

9. The kindergarten children made a total of 420 red flowers, each class has 20 children, an average of 3 flowers per person, how many classes of children participated in this task?