二进制数                   0&1两种元素；

8进制数                   0～7 八种元素；

十六进制数            0～9，a,b,c,d,e,f;

十六进制数      对应十进制数值       对应2进制          心算记忆方法：  2进制数记住4位，XXXX--->ABCD     A：8      B：4     C：2      D：1

0                          0                      0000                                                              ABCD        ：整体可以看作是一个16进制的数

1                          1                      0001                                                            1010  1100  ：可以看作是一个两位数的16进制数

2                          2                      0010                                           因为1010=10 1100=12， 所以1010 1100 可以看作是  10*16^1+12*16^0=172   

3                          3                      0011                笔算方法（短除法）：        数值          二进制 转化        余数

4                          4                      0100                                                           172                   / 2                  0

5                          5                      0101                                                             86                   / 2                  0

6                          6                      0110                                                             43                   / 2                  1

7                          7                      0111                                                              21                  / 2                  1

8                           8                     1000                                                              10                  / 2                  1

9                           9                     1001                                                               5                   / 2                  0

a                          10                    1010                                                               2                   / 2                  1

b                          11                    1011                                                               1                   / 2                  0

c                          12                    1100

d                          13                    1101

e                          14                    1110

f                          15                    1111

十六进制：  0001 0010 0011 0100 0101 0111 1000 1001 1010 1011 1100 1101 1110 1111

十进制：