Examination analysis: one is a Chinese book, and the other is a math book * * * with 10×9=90 methods; One is a Chinese book, and the other is an English book * * * with 10×8=80 methods; There are 8×9=72 ways to take an English book and a math book, so there are10× 9+10× 8+8× 9 = 242 ways to take it * *.

Comments: This topic mainly examines addition principle and the principle of multiplication. Addition principle said: There are n ways to accomplish one thing. The first way, there are m 1 different ways, the second way, there are m 2 different ways, …, the nth way, there are m n different ways, so there are m1+m 2+to complete. The principle of multiplication is: to do one thing, it needs to be divided into n steps. There are m 1 different ways to do the first step, m 2 different ways to do the second step, … and m n different ways to do the n step. Then there are n = m1× m 2× …× m n different ways to do it.