js learning-hexadecimal conversion

1. Decimal to binary:
   modulo two remainder, from bottom to top, fixed process 56----110100

   Convert decimal to binary first, then convert binary to octal or hexadecimal

2. Binary to octal:
   Counting from right to left, every three digits in one group, and 0 to fill in less than three digits, and finally each group of digits is converted to decimal system separately

 110 100  （1*2^1 + 1*2^2 = 6；1*2^2=4）  
 64  4*8^0 + 6*8^1 = 52；

3. Binary hexadecimal system:
   count from right to left, each group of four digits, fill in with 0 if there are less than four digits, and finally each group of digits is converted to decimal

   0011 0100
   34  4*16^0 + 3*16^1=52