Unit 1 preview class

1, count.

Count: when counting, count in a certain order, starting from 1 and counting until the number corresponding to the last object, that is, the last count, which is the total number of such objects.

2. What is the ratio?

Same number: when two objects correspond to each other one by one and there is no surplus, it is said that the number of these two objects is the same.

Ratio: when two objects are in one-to-one correspondence, one of them has surplus, and there is more surplus, and there is no surplus.

When comparing the number of two objects, we can use the one-to-one correspondence method.

extreme

Second unit position

1.

Understand the meaning of up and down: from the position of two objects: up refers to the high object and down refers to the low object.

2. Knowing the past and knowing the future

Understand the meaning of "before and after": Generally speaking, the facing direction is front, and the facing direction is back.

The same object will also change its positional relationship relative to different reference objects.

From this, it is concluded that when determining the front-back position relationship of more than two objects, it is necessary to find the correct reference object, and the relative front-back position relationship will also change with different reference objects.

3. Know the left and right.

Determine the left and right sides according to the positions of your left and right hands. The side where the right hand is located is the right, and the side where the left hand is located is the left.

Important note: When determining the left and right, except for special requirements, the observer's left and right shall generally prevail.

Tisso

Unit 3 1-5 Understanding and Addition and Subtraction

I. Understanding of 1-5

Meaning of the numbers 1 and 1-5: Each number can represent the number of different objects. How many objects are there?

2, 1-5.

From beginning to end: 1, 2, 3, 4, 5.

From back to front: 5, 4, 3, 2, 1.

3. How to write the number 1-5: Write it carefully and neatly according to the shape of each number and its position in Tian Zige.

Second, the specific size.

1, the number in front is equal to the number in the back, which is represented by "=", that is, 3=3, which is read as 3 equals 3. The former number is greater than the latter number, which is indicated by ">", that is, 3 > 2, which is pronounced as 3 greater than 2. The first number is less than the last number, so use "

2. when filling in ">" or "

Third, what number?

1. When determining the arrangement order of objects, first determine the direction of counting, and then start counting from 1, and count to what number, and the order is "which number". It refers to one of them.

2. Distinguish between "a few" and "which one"

"Several" refers to the number of objects, and "Which" refers to only one of them.

Fourth, separation and combination.

Composition of numbers: A number (except 1) is divided into several and several. Divide it into 1 and a few, and then divide it into 1. For example, the composition of 5 is 1 and 4, 2 and 3, 3 and 2, 4 and 1.

When a number is divided into several numbers and several numbers, it should be decomposed in an orderly manner to prevent repetition or omission.

Verb (abbreviation of verb) addition

1, the meaning of addition: put the two parts together, find a * * *, and calculate by addition.

2. Calculation method of addition: To calculate the addition of numbers within 5, you can use methods such as point number, down number, and combination of numbers. Among them, the synthetic calculation of numbers is the most commonly used method.

Sixth, subtraction.

1, the meaning of subtraction: remove (subtract) a part from the total, and calculate how much is left by subtraction.

2. Calculation method of subtraction: When calculating subtraction, you can use countdown, divisor, addition and subtraction, etc.

Seven, zero

1, where 0: 0 means there is no object and it also means the starting point.

2,0 Pronunciation: 0 Pronunciation: zero.

3. How to write 0: Write 0 from top to bottom, from left to right, the starting point and the receiving point should be connected together, and the writing should be smooth and not angular.

Addition and subtraction of 4.0: any number added to 0 will get this number, and any number subtracted from 0 will get this number. Similarly, the subtraction of two numbers is equal to 0.

For example: 0+8=89-0=94-4=0.