**Teaching plan give typical examples**

**Education requirement:**

masters the definition that forms number, show a sign, master the derivation that arranges several formula to reach apply.

**Key difficulty**:

forms number formula and arrange those who count formula to be out of shape

**Education content**:

one, review a query:

1. Multiplication principle:

*N*＝

*M*

_{1}×

*M*

_{2}× ... ×

*M*

_{N} 2. Arrange a definition

3. Exercise:

① by 2, 3, 4, 5, the 6 3 digit that how many can you comprise to did not repeat a figure? (4 × of 5 × 3 ＝ 60 ()

In the element that ② differs from 11, how many does the permutation that allows to take 10 elements share?

(10 × of 11 × 8 × of 9 × 6 × of 7 × 4 × of 5 × 2 ＝ of 3 × 39 916 800 ()

is become

*N*,

*M*when the number is larger, a number that calculate all permutation so is more troublesome.

2, award newly:

1. Arrange several definitions

from

*N*Take out in different element

*M*(

*M*≤

*N*) a number that all permutation of the element, be called from

*N*Take out in different element

*M*