1. Mid-term knowledge points of mathematics in the second volume of the fourth grade of primary school
1, more than 100 million reading methods: ① Grading first, starting from the high position. Read level 100 million, then level 10,000, and finally level 1.
(2) Billions should be read according to the pronunciation of billions, and then the word "billion" should be added at the end. Ten thousand series should be read according to the reading method of ten thousand series, and then the word "ten thousand" should be added after it.
No matter how many zeros there are at the end of each level, don't read them. Other numbers have a "0" or several "0" in succession, all of which are read only.
2, hundreds of millions of words or more:
(1) Write from bits, first write 100 million levels, then write 10,000 levels, and finally write one level.
(2) If there is no unit, just write 0 on the number.
2. The second part of the second book of the fourth grade of primary school, the second part of the middle-term knowledge points of mathematics
1, the size of the comparison number: ① A number with two different digits, the number with more digits is larger.
(2) Two numbers with the same number of digits, starting with a number.
2. Find out the approximate figures:
The mantissa after omitting ten thousand digits depends on the number on one thousand digits; The mantissa after omitting 1 100 million bits depends on the number on1100 million bits.
This method of finding the divisor is called "rounding". Whether it is "rounded" or "decimal" depends on whether the number in the omitted mantissa is less than 5 or equal to or greater than 5. If less than 5, the mantissa will be discarded; If it is equal to or greater than 5, advance to 1 and then discard the mantissa.
3. The third part of the middle-term knowledge points of mathematics in the second volume of the fourth grade of primary school
The area of a square with a side length of 100 meters is 1 hectare. 1 ha = 1 10,000 m2
2. The square with a side length of 1 km has an area of 1 km2.
1 km2 = 1000000 m2
1 km2 = 100 hectare
3, from large units to small units, multiplied by the rate.
From small units to large units, divided by the forward speed.
4. Lines, rays and line segments
Straight line: it can extend to both ends infinitely, and has no end points.
Ray: It can extend infinitely to one end and has only one endpoint.
Line segment: cannot be extended and has two endpoints. A line segment is a part of a straight line.
5. What are the connections and differences between straight lines, rays and line segments?
(1), straight lines and rays can extend indefinitely, so the length cannot be measured.
② The length of the line segment can be measured.
③ A line segment has two endpoints, a straight line has no endpoint, and a ray has only one endpoint.
4. The fourth grade of primary school mathematics Volume II, Mid-term knowledge points, Article IV
1, the pen calculation method of multiplying three digits by two digits: first multiply three digits by two digits, and the last digit of the product is aligned with the two digits; Then multiply the three digits by the number on the ten digits of the two digits, and the last digit of the product is aligned with the ten digits of the two digits; Finally, add the products of the two multiplications.
2, the product change rule:
One factor is a constant, another factor is multiplied (or divided) by several (except 0), and the product is also multiplied (or divided) by several.
3. The price of each commodity is called the unit price; How much did you buy? A * * * price is called the total price.
Unit price × quantity = total price
Unit price = total price ÷ quantity
Quantity = total price/unit price
4. How long a * * * has traveled is called distance; Distance per hour (or per minute, etc.). ) called speed; Hours (or minutes, etc. ) is called time.
Speed × time = distance
Speed = distance/time
5. The fourth grade mathematics in primary school, Volume II, Mid-term knowledge points, Article 5
1, the meaning of addition and subtraction and the relationship between the parts (1) The operation of combining two arrays into a number is called addition.
(2) Adding two numbers together is called addend. The added number is called sum.
(3) The operation of finding the product of two numbers and one of the addends is called subtraction.
(4) In subtraction, the known sum is called subtraction ... subtraction is the inverse operation of addition.
(5) the relationship between the parts of addition:
Sum = Appendix+Appendix
Appendix = Sum-Another Addendum
(6) Subtract the relationship between the parts:
Difference = minuend-minuend
Subtraction = minuend-difference
Negative = negative+difference
2, the meaning of multiplication and division and the relationship between the parts.
(1) The simple operation of finding the sum of several identical addends is called multiplication.
(2) The multiplication of two numbers is called a factor. Multiplied numbers are called products.
(3) The operation of finding the product of two factors and one of them is called division.
(4) In division, the known product is called dividend ... Division is the inverse operation of multiplication.
(5) the relationship between the parts of multiplication:
Product = factor × factor
Factor = product ÷ another factor
(6) the relationship between the parts:
Quotient = divider-divider
Divider = dividend × quotient
Dividend = quotient × divisor
(7) Division with remainder,
Dividend = quotient × divisor+remainder