Summary of mathematics knowledge in sixth grade primary school 1. × copies per share = total copies ÷ each share = total copies ÷ copies = 2 copies per share 1 multiple×××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××× Calculation formula of primary school mathematical graphics; Calculation formula of primary school mathematical graphics; 1 square square square c perimeter s area a side length perimeter = side length × 4c = 4a area = side length× side length s = a. ×a 2 cubic cube v: volume a: side length = side length× side length× 6s table =a×a×6 volume = side length× side length× side length v = a× a. × 2 c = 2 (a+b) area = length× width S=ab 4 cuboid v: volume s: area a: length b: width h: height (1) surface area (length× width+length× height+width× height )× 2s = 2 (ab+ah+BH). Volume = length × width × height V=abh 5 triangle triangle triangle S area A bottom H high area = bottom X height ÷2 s=ah÷2 triangle height = area X 2 bottom triangle bottom = area X 2 height 6 parallelogram S area A bottom H high area = bottom X height S. =ah 7 trapezoid trapezoid trapezoid S area A top bottom B bottom H high area = (upper bottom+) × h÷2 8 circular S area c perimeter base area r: base radius c: base perimeter (1) lateral area = base perimeter× height (2) surface area = lateral area+base area× 2 (3) volume = base area× height (4) volume = lateral area ÷2× radius/kloc. 0 conic conic v: volume h: height s. bottom area r: bottom radius volume = bottom area × height ÷3 total number ÷ total number = formula of average sum and difference problem and formula of difference problem and difference problem (sum+difference ÷ 2 = large number (sum-difference) ÷ 2 = decimal and multiple problem and multiple problem sum ÷. ) = Decimal Decimal × Multiple = Large Numbers (or Decimal+Difference = Large Numbers) Formulas of sum and difference problems in primary schools and formulas of difference problems and difference problems (sum+difference) ÷ 2 = Formulas of decimal and multiple problems and formulas of multiple problems ÷ (Multiple-1) = Formulas of small multiples = Large Numbers (or sum) Formula of Tree Planting Problem Formula of Tree Planting Problem Formula of Tree Planting Problem 1 Tree planting problem on an unclosed line can be mainly divided into the following three situations: (1) If trees are planted at both ends of the unclosed line, Then: number of plants = number of segments+1 = total length ÷ plant spacing-1 total length = plant spacing × (number of plants-1) plant spacing = total length ÷ (number of plants-number of plants then: number of plants = number of nodes = total length ÷. Then: number of plants = number of nodes-1 = total length ÷ plant spacing-1 total length = plant spacing × (number of plants+1) plant spacing = total length ÷ (number of plants+1) 2 The quantitative relationship of trees planted on the closed line is as follows: Profit and loss problem's formula, profit and loss problem's formula, profit and loss problem's formula, profit and loss problem's formula (surplus+deficit), the difference between the two distributions = the number of shares participating in the distribution (large surplus-small surplus), the difference between the two distributions = the difference between the two distributions = the number of shares participating in the distribution; The formula of the meeting question; The formula of the meeting question; The formula of the meeting question; Meeting distance = speed, time = meeting distance; The sum of speed and speed = meeting distance; Meeting time; The formula of the problem; The formula of the problem; The formula of the problem; Distance = speed difference × catching up time = catching up time. Distance ÷ speed difference ÷ speed difference = catching distance ÷ catching time ÷ running water problem ÷ running water problem ÷ downstream speed = still water speed+water speed ÷ still water speed = (downstream speed+countercurrent speed) ÷2 water speed = (downstream speed- Kloc-0/00% = concentration solution weight × concentration = solute weight profit and discount problem formula profit and discount problem formula profit and discount problem formula deduction problem profit = selling price-cost fluctuation = principal × floating percentage profit rate = profit/cost × 100% = (selling price/cost-1) ×/kloc- Interest = principal × interest rate × after-tax time interest = principal × interest rate× time × (1-20%) ((111)) Reading and writing number Reading and writing number1) Integer reading: from high to low, read step by step. When reading the 110 million level, first read according to the reading method of the 100 million level, and then add a word "100 million" or "10 thousand" at the end. The zeros at the end of each stage are not read, and only a few zeros of other digits are read. 2. Writing of integers: from high to low, writing step by step. If there is no unit on any number, write 0 on that number. 3. Decimal reading method: When reading decimals, the integer part is read by integer reading method, the decimal point is read as "dot", and the decimal part reads the numbers on each digit from left to right in sequence. 4. How to write decimals: When writing decimals, the integer part is written as an integer, the decimal point is written in the lower right corner of each digit, and the decimal part is written on each digit in sequence. 5. How to read fractions: When reading fractions, read the denominator first, then the "fraction", and then the numerator. Both numerator and denominator read integers. 6. How to write the fraction: write the fraction first, then the denominator, and finally the numerator and the integer. 7. Reading method of percentage: When reading percentage, read the percentage first, and then read the number before the percentage symbol. When reading, read it as an integer. 8. Writing of percentage: percentage is usually expressed by adding a percent sign "%"after the original molecule instead of a fraction. The rewriting number of (((2222))) number is a large multi-digit, which is often rewritten as a number in the unit of "10000" or "1000 million" for the convenience of reading and writing. Sometimes, if necessary, you can omit the number after a certain number and write it as an approximation. 1. exact number: in real life, for the convenience of counting, larger numbers can be rewritten into numbers in units of ten thousand or hundreds of millions. The rewritten number is the exact number of the original number. For example, 1254300000 is rewritten into ten thousand, and the number is125430000; Rewritten into a number of 65.438+025.43 billion in units of hundreds of millions. 2. Approximation: According to the actual needs, we can also use a similar number to represent a larger number and omit the mantissa after a certain number. For example: 13024900 15 The mantissa after omitting 100 million is1300 million. 3. Rounding method: If the highest digit of the mantissa to be omitted is 4 or less, the mantissa is removed; If the digit with the highest mantissa is 5 or more, the mantissa is truncated and 1 is added to its previous digit. For example, the mantissa after omitting 3.459 billion is about 350,000. After omitting 472509742 billion, the mantissa is about 4.7 billion. 4. Size comparison 1. Compare the sizes of integers: compare the sizes of integers, and the number with more digits will be larger. If the numbers are the same, view the highest number. The greater the number in the highest place, the greater the number; The number in the highest bit is the same. Just look at the next bit, and the bigger the number, the bigger it is. 2. Compare the sizes of decimals: first look at their integer parts, and the larger the integer part, the larger the number; If the integer parts are the same, the tenth largest number is larger; One tenth of the numbers are the same, and the number with the largest number in the percentile is larger ... 3. Compare the sizes of scores: the scores with the same denominator and the scores with the largest numerator are larger; For numbers with the same numerator, the score with smaller denominator is larger. If the denominator and numerator of a fraction are different, divide the fraction first, and then compare the sizes of the two numbers. ((three, three, three, three, three, three), three)) The reciprocal of the number 1 Decimal component number: There are several decimals originally, so writing a few zeros after 1 as the denominator and removing the decimal point after the original decimal point as the numerator can reduce the number of quotation points. 2. Fractions become decimals: numerator divided by denominator. Those that are divisible are converted into finite decimals, and some that are not divisible are converted into finite decimals. Generally three decimal places are reserved. 3. A simplest fraction, if the denominator does not contain other prime factors except 2 and 5, this fraction can be reduced to a finite decimal; If the denominator contains prime factors other than 2 and 5, this fraction cannot be reduced to a finite decimal. 4. Decimal percentage: Just move the decimal point to the right by two places, followed by hundreds of semicolons. 5. Decimal percentage: Decimal percentage, just remove the percent sign and move the decimal point two places to the left. 6. Convert fractions into percentages: usually, first convert fractions into decimals (three decimal places are usually reserved when they are not used up), and then convert decimals into percentages. 7. Decimalization of percentage: First, rewrite percentage into component quantity and put forward a quotation that can be simplified to the simplest score. (((4444))) The divisibility of the divisible number of a number is 1. A composite number is usually decomposed into prime factors by short division. Divide this complex number by a prime number until the quotient is a prime number, and then write the divisor and quotient in the form of multiplication. 2. The way to find the greatest common divisor of several numbers is to divide the common divisors of these numbers continuously until the quotient obtained is only the common divisor of 1, and then multiply all the common divisors to get the product, which is the greatest common divisor of these numbers. 3. The method of finding the least common multiple of several numbers is: divide by the common divisor of these numbers (or part of them) until it is coprime (or pairwise coprime), and then multiply by all the divisors and quotients to get the product, which is the least common multiple of these numbers. 4. Two numbers that become coprime relations: 1 and any natural number coprime; Two adjacent natural numbers are coprime; When the composite number is not a multiple of the prime number, the composite number and the prime number are coprime; When the common divisor of two composite numbers is only 1, these two composite numbers are coprime. (((5555))) Reduction and General Fraction and General Fraction and General Fraction and General Fraction 1, reduction method: use the common divisor of numerator and denominator (except 1) to remove numerator and denominator; Usually, we have to separate it until we get the simplest score. 2. General fractional method: first find the least common multiple of the denominator of the original fraction, and then turn each fraction into a fraction with this least common multiple as the denominator. Decimal 1, the meaning of decimal Divide the integer 1 into 10, 100, 1000 ... The scores, percentages and thousandths obtained can be expressed in decimals.