Before moving to actual subnetting, you need to remember the powers of 2 i.e. the value of 2 multiplied as many times as the given exponent. For example 24 = 2 x 2 x 2 x 2 = 16. Table 2-8 lists the first 14 values. It is not necessary to remember them all, but do remember that each value is twice the previous one. The more you remember these values, the easier it will be to subnet on your CCNA exam