Key points of knowledge
1, "careful calculation"-the divider is the fractional division of an integer.
(1), the meaning of fractional division: The meaning of fractional division is the same as that of integer division, which is the operation of finding the other factor by knowing the product of two factors and one of them.
(2) Calculation method of fractional division by integer: Fractional division with integer divisor is similar to integer division, as long as the decimal points of quotient and dividend are aligned.
2. Visit the museum-integer divided by integer quotient is fractional division of decimal.
When an integer is divided by an integer, the quotient is a decimal. The calculation method of fractional division is as follows: first, do it according to the law of integer division. If there is a remainder at the end of the dividend, fill in 0 to continue the division.
3. People who have been on the phone for a long time-division is the division of decimals.
(1), the law of quotient invariance: the dividend and divisor expand or shrink by the same multiple at the same time (except 0), and the quotient remains unchanged.
(2) Calculation method of fractional division with divisor as decimal: The divisor and divisor should be expanded by the same multiple, so that the divisor becomes an integer, and then the calculation is carried out according to the method of dividing the decimal by the integer.
4. Approximation of RMB exchange rate-product sum quotient
Approximation method: calculate the approximate value of the product accurately first, and then approximate it according to the requirements of the topic; The approximate value of the quotient is directly divided by one bit according to the requirements, and then the approximate value is obtained according to the requirements of the topic. Note: Sometimes there will be reluctance, and you should find the approximate figures according to the characteristics of the topic.
5. "Who climbs fast"-cyclic decimal
(1), circular phenomenon: there are many times in life that are repeated in turn. Such as sunrise and sunset, time ...
(2) Cyclic decimals: One or several numbers appear repeatedly from a certain place in the decimal part, and such decimals are called cyclic decimals.
(3) Rounding method will be adopted to approximate the circular decimal, which is the same as decimal. Keep a few decimal places and look at the next decimal place.
6. "TV advertisement"-the basic operation of decimal system.
(1), fractional division and multiplication and division are mixed operations, and the operation order is the same as that of integers.
(2) Decimal elementary arithmetic and integer elementary arithmetic are calculated in exactly the same order.
Passion Olympics
(1) Through all kinds of information provided by the "Olympic Games", comprehensively apply the learned knowledge and methods to solve related problems.
(2) By solving the related problems in the Olympic Games, we can realize the connection between mathematics and physical education and further appreciate the value of mathematics.