Real number: the collective name of rational number and irrational number, like the root number 2 0 5.

Even number: A digital image divisible by 2 2 4 6.

Prime number: a natural number with only two factors: 1 and itself, just like 2 3 5 7 (ha, I can recite the prime number table. )

Approximate quantity:

Rational number: If an integer is divisible by another integer, then the second integer is the divisor of the first integer, such as 6. The divisor is 1, 2, 3, 6.

Irrational number: infinite loop decimal symbol 2

Common divisor: If an integer is a divisor of several integers at the same time, it is called their "common divisor". Like the common divisor of 2 and 4, there is12.

Common multiple: The common multiple of two or more numbers is called the common multiple of these numbers. For example, the common multiple of 2 and 4 is 4 8 16 32 64. ....

Natural number: the number used to measure the number of things or to indicate the order of things is a non-negative integer ~ like 0 1 2.

Positive integer: an integer image greater than 0 1 2 3 4.

This, this, this ... is not from junior high school, is it? ...

CuA=B CuB=A