Converting a Hex Representation to Decimal

To convert a hexadecimal representation of an integer to base 10, write the integer as a sum of hex digits times the corresponding power of 16 for each digit's position. Then, write the digits and the powers of 16 in base ten, and do the arithmetic.

31A (base sixteen) = 3 × sixteen2 + 1 × sixteen1 + A × sixteen0

                   = 3 × 162 + 1 × 161 +  10 × 160

                   = 3 × 256 + 1 × 16 +  10 × 1  =  79410

You don't have to remember powers of 16 to do this conversion. All you need is powers of 2. For example,

162  =  24 × 24  =  
28  =   256.

Another example:  

163  =  24 × 24 × 24  =  
212  =  22 × 210  =  4K