Ways to find common problems:

Basic method-look at the increase:

(1) If the increments are equal (actually arithmetic progression): compare each number with its previous number;

(2) if the increase is not equal, but the increase is equal (that is, the increase is equal, that is, the increase is arithmetic progression);

(3) The growth rate is unequal, but the growth rate increases year-on-year, that is, the growth rate increases geometrically;

(4) Unequal increase and unequal increase (that is, unequal increase).

2.

Think about solving problems:

(1) serial number: to find the topic of regularity, usually a series of quantities are given in a certain order, which requires us to find the general law according to these known quantities.

(2) Common factor method: multiply each digit by the least common factor, and then find the law to see if it is related to n, or 2n, 3n.

(3) Look at the examples;

(4) Some people can subtract the first number from each number at the same time to form a new series starting from the second number, and then use the skills of (1), (2) and (3) to find out the relationship between each number and its position. Then add the first number to the found law and restore it to its original appearance.

(5) Some can add, multiply or divide each number at the same time to form a new series, and then find out the law and return to the original point.