High school mathematics elective 2-3 cases 7 have 6 people in a row. How many arrangements do three non-adjacent people have? How to solve the exclusion method? Detailed explanation

Method 1: the exclusion method is difficult and empty. A33 (the remaining 3 people are arranged freely) times A43(3 people and 4 people, all arranged) = 144.

Method 2: The exclusion method is always * * A66, A, B and C together, and then completely arranged, A33*A44, A, B and C together, C32, and then arranged into a whole A22, which is equivalent to five, and two of them (and then a whole A22) cannot be arranged together, so the arrangement method is, A55-

It is strongly recommended not to exclude methods, which is not suitable for this topic.

Is the ability requirement of "three views" in the new curriculum standard of senior high school to understand, master or master?

A reborn mathematician

Teaching plan of "small animals moving to new houses" in middle class

Find the most common mathematical quick calculation method. (decline advertising! )

How many people can sit at a round table with a diameter of 3.5m?

Shi Tingting Mathematics

How about 24 o'clock?

Mathematical story 200 words: the great mathematician

Math problems in grade one. On the operation of algebraic expressions.

Is Wan Wei Top Students Suitable for PEP?