CCNA 18

Let's review the IPv4 basics. It is a dotted-decimal, 32-bit address, represented with four decimal octets separated by dots. An example is 10.10.10.10. A host address can be one of three different classes. Class A has the first octet as the subnet address, Class B has the first two octets as the subnet address, and Class C has the first three octets as the subnet address. The rest are known as host bits which represent a host in a subnet. IP operates at Layer 3 of the OSI model and is used for path determination.
IPv4 is a 32-bit address. IPv6, on the other hand, is 128-bit. IPv6 consists of 8 sets of 4 hexadecimal numbers separated by colons. An example is 1234:5678:9ABC:DEF0:5678:9101:1121:3141. With IPv6, every square inch of planet Earth can be assigned 3.7 million addresses. Every 3 square feet of the milky way galaxy can have an IP address. You can give a person the entire IPv4 range every second for 2512308552583217199186 years. It is likely that everything manufactured in the future would have IP addresses.

In the Cisco examination you would have to work with numbers without a calculator. To quickly convert decimal to binary, use the following system:

180=
1*128+
0*64+
1*32+
1*16+
0*8+
1*4+
0*2+
0*1

180 would then be 0b10110100.

41=
0*128+
0*64+
1*32+
0*16+
1*8+
0*4+
0*2+
1*1

41 would then be 0b00101001.

0b00110110=
0*128+
0*64+
1*32+
1*16+
0*8+
1*4+
1*2+
0*1

0b00110110 would then be 54.

0b10010110=
1*128+
0*64+
0*32+
1*16+
0*8+
1*4+
1*2+
0*1

0b10010110 would then be 150.

When you are actually used to this, you can do this mentally. This may not be the best way for you. Understanding the formulation of a formula is more important than the formula itself.