Current location - Training Enrollment Network - Mathematics courses - What are the answers on the second page of the second volume of the fourth grade mathematics oral arithmetic training?
What are the answers on the second page of the second volume of the fourth grade mathematics oral arithmetic training?
As follows:

This part of the extended materials mainly examines the knowledge points of division:

If ab=c(b≠0), the operation of finding another factor A by multiplying the product C and the factor B is division, which is marked as c÷b and pronounced as C divided by B (or B divided by C). Among them, c is called dividend, b is called divisor, and the result of a operation is called quotient.

The dividend is enlarged (reduced) by n times, and the quotient is correspondingly enlarged (reduced) by n times under the condition that the divisor is unchanged. The divisor is expanded (reduced) by n times, while the dividend is unchanged, and the quotient is correspondingly reduced (expanded) by n times.

Dividing by two divisors in succession is equal to dividing by the product of these two divisors. Sometimes simple operations can be performed according to the nature of the division. For example, 300÷25÷4=300÷(25×4) divided by a number is equal to the reciprocal of this number.

Short division, commonly known as "short division", is suitable for fast division, synchronous division of multiple integers (so it is often used to find the greatest common factor and the least common multiple), binary digital conversion and so on. , pay more attention to multiple tests and division of prime factors (serial multiplication). Most processes only need to use the multiplication table of 99 and a few multiplication factors of integers above 9.

If the number A is divisible by the number B, it is called a multiple of B and B, and it is called a factor ... Both factor and multiple represent the relationship between one number and another number and cannot exist independently. If we can only say that 16 is a multiple of a certain number and 2 is a factor of a certain number, then we cannot say that 16 is a multiple and 2 is a factor in isolation.

"Multiply" and "multiple" are two different concepts. "Times" refers to the quotient of dividing two numbers, which can be integer, decimal or fraction. "Multiply" is only within the divisible range of numbers. Compared with "divisor", it represents a number that can be divisible by a natural number and must be a natural number.

Several natural numbers, common factors of these numbers, common factors; The largest one, the greatest common divisor of these numbers. For example, the common divisors of 12 and 16 are 1, 2 and 4, the largest of which is 4, which is the greatest common divisor of 12 and 16, and is generally recorded as (12 and/kloc-). The greatest common divisor of 12, 15 and 18 is 3, and it is (12, 15, 18)=3.