Arithmetic progression scored about 20 in the college entrance examination, accounting for 13% of the total score. Sequence is one of the main contents of high school mathematics, which occupies a considerable proportion in the annual college entrance examination mathematics questions. General 2-3 questions (1~2 questions are selected or filled in, 1 questions are solved). The difficulty of choosing or filling in the blanks is controlled in the middle, and it is generally easier to answer questions; The 1 solution-type big questions are arranged in the second half of the test questions, most of which are above average or even difficult, which is a hot and difficult point in the mathematics of college entrance examination.