Summary of mathematical knowledge points in the first volume of senior one.
1, number: according to the number of objects, it can be represented by 1 1-20.
2. Sequence: 1 1-20 The sequence is: 1 1, 12, 13, 14, 15,/kloc.
3. Comparison size: comparison can be made according to the order of numbers, and the number at the back is always greater than the number at the front, or according to the composition of numbers.
4. Composition of the number 1 1-20: All of them are composed of 1 tens and several ones, and 20 is composed of two tens.
Such as: 1 ten and five 15.
5. Number of digits: the first digit on the right is one digit, and the second digit is ten digits.
6. 1 1-20 How to read each number: read dozens of digits from high places and several digits. Pronunciation of 20, 20 is pronounced: 20.
7. Write numbers: When writing numbers, write against them. If there are 1 tens, write 1 on the ten, and if there are two tens, write 2 on the ten. If there are several 1, write a few on each bit, and if there is no unit on each bit, write a 0.
8. Ten plus several, ten plus several and the corresponding subtraction.
(1), 10 plus several and the corresponding subtraction calculation method: 10 plus several to get ten, ten minus several to get ten, and ten minus ten to get several.
For example, 10+5= 15,17 =10, 18- 10=8.
(2) Calculation method of ten plus several and corresponding subtraction: When calculating ten plus several and corresponding subtraction, you can use the composition of numbers to calculate, or you can add or subtract the numbers in units of one and then add the whole ten.
(3) Add and subtract the names of each part:
In the addition formula, the numbers before and after the plus sign are called addends, and the numbers after the equal sign are called sums.
In the subtraction formula, the number before the minus sign is called the minuend, the number after the minus sign is called the subtraction, and the number after the equal sign is called the difference.
9. Solve the problem
To find how many numbers are between two numbers, you can use counting method or graph method. You can also use the calculation method (subtract large numbers from 1).
Knowledge points of "addition and subtraction within 100" in senior one mathematics.
1. Ten digits are added and subtracted, and one digit is added and subtracted.
1, carry-free addition 20+30=5067+2=6968+30=98.
2. Subtraction without abdication 80-50=3069-2=6798-30=68
Second, carry addition (add up to ten)
1, make up ten songs: one for nine, two for eight, three for seven, four for six and five for ten. (Note: Two figures rounded to ten are complementary.)
2.20 Carry-in addition: decimal method: 8+72= 15, ten digits plus 1, one digit minus the complement (2+8= 10, 2 is the complement of 8).
3. 100 plus 362+8=44 decimal extraction method: the digits are connected by arcs, and the digits are added to 1 and subtracted. (The method is the same as within 20)
Third, abdication subtraction.
1, abdication less than 20: ten-break method: 16 1-9=7 digits' complement.
2. If abdication is less than 100: 36 1-9=27, refining method: units are connected by arcs, ten units are subtracted by 1, and units are supplemented.
Mathematics learning methods and skills
(A) with "add up to ten" oral calculation
According to the characteristics of the formula, apply laws and properties to "round" the operation data:
1. Appendix "Overview"
For example, 14+5+6=? Enlighten students: Add up several figures. If several numbers add up to an integer 10, you can change the position of the addend and add up several numbers.
2. Use the nature of subtraction to "round off"
For example, 50- 13-7 can inspire students to say the thinking process, say several oral calculation methods and let students sum up by comparison: subtract several numbers from a number continuously. If the sum of subtraction can make up an integer, you can add the subtraction first and then subtract it. This kind of oral calculation is simple and convenient.
3. Multiplication factor "rounding"
Such as 25× 1? The product of 4× 4, 25 and 4 is 100, and the result can be calculated directly by mouth.
(B) the use of "decomposition" oral calculation
Is to "disassemble" one number in the question and perform an operation with another number, such as 2? 5×32, the original formula becomes 2? 5×4×8= 10×8=80。
(C) using some quick calculation skills for oral calculation
1. Two digits are quickly multiplied by the first and last digits 10.
That is, multiply the number on one of the ten digits by 1, and the product is one hundredth and one thousandth of the product of two numbers, and then the product of the numbers on two numbers is one and one tenth of the product of two numbers. For example, 14× 16=224(4×6=24 is a unit, 10 digits, (1+ 1)× 1=2 is a hundred digits).
2. Fast multiplication of two digits of head difference 1 and tail difference 10. That is to say, the square of the ten digits of the larger factor MINUS the square of its single digits. Such as: 48×52=2500-4=2496.
3. Use the "benchmark number" for quick calculation.
For example, 623+595+602+600+588 can choose 600 as the base number, first accumulate the difference between each number and the reference number, and then add the product of the base number and the number of items.
(d) Memorizing commonly used data
Such as: 65438+ the square of 0 ~ 20 of each natural number; To read the word "practice" well means to practice oral arithmetic often. The formation of speech ability can only be achieved through routine training, and the training should be diversified.
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