I. Four operations of addition, subtraction, multiplication and division of fractions

1. Fractional addition: Fractions with denominator are added, denominator is unchanged, and numerator is added; To add fractions with different denominators, we must first divide them, that is, find the least common multiple of the two denominators, then convert the two fractions into fractions with the same denominator, and then add them between molecules.

2. Fractional subtraction: subtraction with denominator, denominator unchanged, molecular subtraction; The subtraction of fractions with different denominators also requires division first and then subtraction between molecules.

3. Fractional multiplication: The multiplication algorithm of fractions is numerator multiplied by numerator and denominator multiplied by denominator. If you can reduce it, reduce it first. That is, cross-multiply first, and then subtract points.

4. Fractional division: The algorithm of fractional division is reciprocal multiplication, and the product is quotient. That is, the dividend is multiplied by the dividend in turn.

Second, the simplification of scores.

Simplification is an important step in quartering operation. By finding the greatest common divisor of the numerator and denominator, and then dividing the numerator and denominator by this greatest common divisor, you can get the simplest score.

Third, the application of scores in real life.

The operation of quartering will not only appear in math problems, but also be used in many scenes in life. For example, we need to use four operations of scores when calculating discounts, distributing goods and calculating proportions.

Generally speaking, the knowledge points of the fifth unit of mathematics in the first volume of the sixth grade mainly focus on the four operations of fractions, including addition, subtraction, multiplication, division and simplification of fractions. When learning and mastering these knowledge points, students need to understand and practice with examples in order to better master these knowledge points and use them flexibly in real life.