Seeking interesting mathematics problems suitable for junior one Am I too greedy That's it, anthracene

Seeking interesting mathematics problems suitable for junior one Am I too greedy That's it, anthracene

Suppose that the number of people who buy sheep is a 5A + 45 = 7a + 3A = 21, and the price of sheep is 5 * 21 + 45 = 1502. There are odd stones placed every one meter along the straight line, and the stones should be concentrated in the middle, from the rightmost

Interesting math problems in primary school

Little bear's mother is ill. In order to earn money to treat her mother's illness, little bear gets up at dawn every day and goes fishing in the river. One day, little bear just sets up a fish stand, and fox, black dog and old wolf come. Little Bear sees a customer coming, and says, "do you want to buy fish? I just caught this fish. It's fresh!" the fox rummages

Mr. Li bought new books for the school library with 2000 yuan. He bought 15 sets of the two books, 84 yuan for the first and 42 yuan for the second
Does Mr. Li have enough money? How much more, how much less?

84*15+42*15=1890

It is known that M is greater than or equal to 2, n is greater than or equal to 2, and m and N are positive integers. If m ^ n is "decomposed" as shown in the following figure, there are three descriptions:
2²｛①1 ②3 3²｛①1 ②3 ③5
2 {1 3 2 5 3} 3 {1 7 2 9 3 11
The fourth power of 2 {1 7}, the fourth power of 9 3 {1 25}, 27}, 29

(1) According to the law of the exponent of 2, we can get 25 "decomposed" into 15, 17 sum to answer;
(2) (3) according to the rule that the index is 3, the solution is given. (1) it is observed that 25 can be "decomposed" into 15 + 17,
So the biggest number is 17;
（2）∵23=3+5,33=7+9+11,
∴43=13+15+17+19,
The smallest number is 13;
(3) When m = 5, 53 = 21 + 23 + 25 + 27 + 29,
The smallest number is 21, so this question is wrong
Correct (2), only 1

Cone···
1. In order to measure the volume of potatoes, Xiao Xin first cut a potato into a rectangle which is 4cm long, 3cm wide and 1cm high, and then weigh 7.2g with a balance. Then he weighed 180g with a balance. What's the volume of this potato?
2. A conical container, measuring the bottom diameter of 12 cm and the depth of 10 cm from the inside, fill it with water and pour it into a cube container with an edge length of 8 cm. How many cm is the water depth? (the number is kept as an integer)
I don't know how to work it out····

1.180 ÷ 7.2 × 4 × 3 = 300 cm3
12 × 10 × 1 / 3 △ 8 square = 5 / 8 cm

Four 3 cm square, put together into a rectangle, the rectangle perimeter and area of each?

Perimeter: 3 × 4 × 4-3 × 6 = 30 (CM)
Area 3 × 3 × 4 = 36 (cm2)

The square of 1.2345 + (0.7655) + 2.469x0.7699 is
Calculation by simple method

It should be 4.0108636

It takes 25 seconds for a train to pass through a 250 meter long tunnel and 23 seconds to pass through a 210 meter long tunnel. How long is the train?

Suppose the train length is x meters
Because the train speed is equal
So you can make an equation
(250+x)/25=(210+x)/23
Solve the equation to get x = 250 (m)
A: the train is 250 meters long

As shown in the figure, O is the intersection of diagonal lines of rectangular ABCD, AE bisects the angle bad, and the angle AOD is 120 degrees. Calculate the degree of angle AOE
As shown in the figure, O is the intersection of diagonal lines of rectangular ABCD, AE bisects the angle bad, and the angle AOD is 120 degrees. Calculate the degree of angle AOE
E is on BC. AC and BD are rectangular diagonals, intersecting with point o

As o is the intersection of diagonal lines of rectangular ABCD, we know that OA = ob = OC = od = AC / 2 = BD / 2 (the diagonal lines of rectangle are equal and equally divided each other) ∵ AOD = 120 ∵ oad = ∵ ODA = ∵ CBD = ∵ ACB = (180 ° - 120 °) / 2 = 30 ∵ AOB = 180 ° - 120 ° = 60 ° AB = bdsin30 ∵ BD / 2 = Bo and AE equally divided ∵ bad, ∵ BAE = 90

In order to realize China's lunar exploration plan, the distance between the earth and the moon is 2.56 seconds when the laser is sent to the moon and returns to the ground_____ Rice

128 x 300 km = 384000 km