Binary and hex conversion drill

Fast binary conversion is the base skill under subnetting and IPv6. This drill covers 8-bit decimal and binary, two-digit hexadecimal, and the mask octets 128 to 255.

The method

• Binary place values for one octet, left to right: 128, 64, 32, 16, 8, 4, 2, 1. Add the values that have a 1.
• Hexadecimal digit = 4 bits. A two-digit hex number is high digit × 16 + low digit; for example C0 is 12 × 16 + 0 = 192.
• Mask octets only come in eight forms: 128, 192, 224, 240, 248, 252, 254, 255, adding one leading 1-bit at a time.

Use the results in subnetting step by step and in the subnetting trainer. Binary is tested in CCNA 200-301 and Network+ N10-009.