Reduction: Finding the greatest common divisor of denominator and numerator. The simplest score.
Addition and subtraction of fractions: numerators with the same denominator are directly added and subtracted. Denominators are different, so we must divide them into the same denominator and then add and subtract the numerator.
Multiplication and division of fractions: division is usually converted into multiplication for calculation, which is convenient for fraction reduction. . .
(For reference only. . . You need more practice to get something. I wish you progress in your study. )