Winter Vacation Homework for Second Grade Math knowledge in life, please know a few

Cats often wrap their bodies in a ball when they sleep, which also has mathematical knowledge, because the ball has the smallest surface area and is wrapped in a ball to sleep, which is not easy to dissipate heat.

The triangle has stability, and the manhole cover is not square when it is round, because the square manhole cover is easy to fall.

Triangle. Chickens and rabbits in the same cage.

The shortest straight line between two points.

The triangle has stability (generally seen in architecture).

I'm sorry.. I can't think of it.

The triangular thing is more stable.

1. Earth Public**

The cyclic motion of an object along a certain orbit centered on another object; The orbit can be circle, ellipse, hyperbola, or parabolic.

2. The earth is self-sufficient

The Earth rotates from west to east on its axis of rotation, rotating counterclockwise from the North Pole and clockwise from the South Pole. The Earth's axis of rotation is angled to the ecliptic plane, perpendicular to the equatorial plane.

3. Clock turning:

Mechanical clocks use the mainspring as the driving force of the prime mover system, through a set of gears composed of a drive system to promote the escapement governor to work; The escapement governor then controls the speed of the drive train in turn; The speed of the drive train is controlled by the escapement governor, so the pointer can indicate the time on the dial according to a certain rule; The upper pluck hand is a mechanism that tightens the spring or toggles the hands.

4. The four seasons change:

The four seasons that alternate throughout the year, namely spring, summer, autumn, and winter, are three months each. The four seasons of the year are formed because the earth revolves around the sun. Due to the existence of the yellow-red angle, the annual variation of the direct sunlight point moving back and forth between the north and south latitudes of the earth is 23°26, which causes the seasonal change of the height of the sun at noon and the seasonal change of the length of day and night.

5. Traffic light:

It generally consists of red lights, green lights, and yellow lights. A red light means no traffic, a green light means permission to pass, and a yellow light means a warning. In the early days, there were only two colors, red and green, but later after improvement, a yellow light was added, a red light indicated stop, a yellow light indicated preparation, and a green light indicated passage.

First question: 2 kinds 1, my dad 2, dad, me.

The second question is boring: 6 kinds of 1, my parents and parents.

2. My mom and dad.

3. Dad, me, Mom.

4. Dad, Mom, Me.

5. Mom, Dad, me.

6. Mom, me, Dad.

Second-grade children have several different methods for this kind, it is best to use the enumeration (example of Zi Lachun) method, through the examples of the list of equations to let children understand the equation, for example, the second question is: 2 3 = 6 (kind) This kind of question to determine who the first one is, you can specify at will, in the equation 2 means that there are 2 kinds of standing methods after determining who the first one is (for example, there are 2 kinds after determining the first one is me, my father and mother 2, my mother and father), 3 means that the first position can have 3 kinds (before the wheel of resistance to dad, mother, I) is 3 out of 2, so it's 2 3 = 6 (kinds) I hope it will be useful to you, and you can ask me questions.

Divide by 4 and leave 3 for ......Multiples of 9 have ......

Both are 27

So there are 27 storybooks in this batch.

There is no good way to do this, it is generally a test and can be answered directly.

There must be multiplication and division, and the question should be carefully examined! If there is multiplication and division 3 3 + 3 3 = 2

There can't be an answer.,If it's a brain teaser or something like that, it's too boring.,You can use permutations and combinations.,Try them one by one.,You will find that there's no answer.。。。

If you can multiply and divide, it's easy to do

These 3s must be multiples of 3 after addition and subtraction, so it is impossible to have a solution from a purely mathematical point of view.

Solution 1:

Common Parts Then assign the following 2 sets of numbers to any circle.

Solution 2: Public part

Then assign the following 2 sets of numbers to any circle.

Reason: 1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 = 36 then 21 * 2 = 42

So the common part is 42-36=6

Then you can assign it.

Grade 2 mixed arithmetic questions.

1. Write down the numbers of the following questions directly.

2. Off-line calculation.