Later, I often associate it. The following is what I think is easy to communicate:
1. The first thing that comes to mind is 18 1 and 775 (two bus line numbers that I often met on my way home with my little granddaughter a few years ago). That's because during the nearly eight years with my little granddaughter, when she just learned to read simple children's songs, we were on the same bicycle, writing and reading in various forms repeatedly.
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Family songs
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? Guo Ye walks with him, if you ask Ye Ying;
? Ride through the rain, rap and listen to each other.
? Hold an umbrella with a small hand and pull a cart with a big hand;
? The umbrella is crooked to cover your eyes, so correct it quickly.
If you see shouting, 7? 7? 5 roads;
It has friends. 1? 8? 1 road.
So go home and want to meet my parents;
Enjoy the scenery all the way, and the police
? The song of going home was read by my little granddaughter sitting in a small chair hanging in front of this car and recited it by heart.
2. What can "2" stand for?
? When the little granddaughter just learned to count, she often said: People have two hands and two feet; Two eyes, two ears ("two" and "ears" are homophonic in Chinese, that is, there are as many elements in a certain set as ears, using the equation. It is said that ancient Indians often used eyes to represent "2"? ); And "2" is the smallest number representing "many" and the smallest prime number in number theory ... You may learn anatomy in the future and find "two kidneys" and so on ... Many animals and plants have similar views. ...
? 3. How many formulas can be listed from the three "2" in 222?
Using three "2" in 222, we get:
? 2+2+2=
? 2-2+2=
? 2+2-2=
? 2-2-2=
The first group is addition, subtraction and mixed operation. Note the position change of+and-between three 2s. This discovery process is an excellent minimalist case to cultivate children's "classification" thoughts and methods! The process of doing these questions is also very interesting. Let friends play freely and adults observe the operation sequence. Maybe it's more than "from left to right"! There is also a negative number in the result of the last formula. If children haven't learned negative numbers, this is an excellent time to introduce the concept of negative numbers! Please use your wisdom to seize the opportunity, and the children will appreciate you! Really can "play with middle school", and finally sum up yourself, don't force it, let it be, and enjoy a real education with each other. ...
? 2×2×2=
? 2×2÷2=
? 2÷2×2=
? 2÷2÷2=
This second group is a mixed operation of multiplication and division, which can imitate the discussion and interaction of the first group.
? 2+2×2=
? 2+2÷2=
? 2—2÷2=
? 2—2×2=
? This third group is a mixed operation of addition, subtraction, multiplication and division. Pay attention to the introduction of operation "classification" and "operation sequence", which can still be discussed interactively.
? (2-2)? =
? 2=
(2+2)? =
(2? )? =
……
? This fourth group also involves the operation of "power". As long as we always pay attention to the principle study, grasping the essence of power is to do "the same multiplication and the same multiplication", which may make the friends who have only learned multiplication solve this kind of problem smoothly (the above answers are easy to get, and it may be that each individual's operation path is different. It may be more beneficial to find a vivid inquiry process and educate people. ) ... There are many interesting and useful things waiting for you to discover!
The magical use of "2"
In the past, there were many bowls and plates used in rural weddings, but not so many in one family. Everyone raised money to buy a lot of bowls and plates, and one person kept them. Whoever has a wedding can borrow it and return it immediately after use. It's very convenient. After a long time, the breeder finds it troublesome to count each time. He thought of a way to pay for the plates you borrowed without counting them. For example, there are 65,438+0,000 plates, and he puts them in 65,438+00 boxes. The number of plates in this 10 box is 1, 2, 4, 8, 16, 32, 64,128,256,499? So no matter how much you borrow, you just need to move the box according to the numbers. If you borrow 50 plates, 2+ 16+32=50, move boxes 2, 5 and 6. 80 boards, 64+ 16=80, just move boxes 5 and 7; In order to find the number of boxes conveniently, you can also express the number of plates in each box in the form of power to analyze the equation, for example, 100 plates: because 100=2? (4)+2? (32)+2? (64)
So just move boxes 3, 6, 7 (each index plus 1 is the box number, such as 2? The median index is 5, 32=2? The number of boxes per disk is 6, which can be seen from the number of disks of each of the ten boxes listed in the original list. )。
732 plates: because
732= 1(2? )+8(2? )+32(2? )+64(2? )+ 128(2? )+499。 So, just move the box 1, 4, 6, 7, 8, 10 ... you can see if you can get what you want.
Exploration is still on the road ~
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Bai Jiaxiang of An Tian? 202 1. 10.3.
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