1, the meaning of the score: divide a whole into several parts on average, take out several parts, and divide these parts by the total number to be several parts of the whole. Writing: 4/5.

Is to divide the whole into five equal parts and take out four of them.

2. Score: It is the proportion of one part to the whole after a whole is divided into several parts.

Score: the meaning of the same score. The former "several" indicates the total number of copies divided as a whole, and the latter "several" indicates the number of copies taken out.

3. The more the average share of a whole, the smaller the number represented by each share. This involves a concept, the unit is "1", that is, the whole is regarded as one.

4, scoring comparison method:

Molecules are the same, denominator is small, denominator is big and small. It goes without saying that the fewer shares a whole is divided into, the greater the number represented by each share.

(2) Denominators are the same, macromolecules and micromolecules. It is understood that a whole is divided into the same number of copies, and the fewer copies are taken out, the smaller the amount.

5. Fractional addition and subtraction:

① Calculation method of addition and subtraction of fractions with the same denominator: addition and subtraction of fractions with the same denominator, denominator unchanged, numerator addition and subtraction.

(2) Calculation method of how many fractions are subtracted from 1: When calculating how many fractions are subtracted from 1, write1as the denominator of the subtraction before calculation.

3 addition and subtraction of general fractions: divide first, then add and subtract. Division is to turn the denominator into the least common multiple of two denominators.

6. Find the fraction of one number to another: just divide this number by another number;

7. Find the fraction of a number: just multiply this number by a fraction;

8. Know what the score of a number is, and find this number: just divide it by a score.