The divisor of a fraction is called the divisor of the numerator and denominator.

(2) The basis of fractional reduction: the basic properties of fractions.

(3) Fractional reduction method:

Factorize the numerator and denominator of the fraction, and then remove the common factor of the numerator and denominator.

(4) The concept of the simplest score:

When the numerator and denominator of a fraction have no common factor, it is called simplest fraction.

For example, 15/3, the numerator and denominator are rounded at the same time, and the result is 5.