Binary & Hex

Exam Tips - Binary & Hexadecimal

Most common exam questions:

• "Convert X to binary" → Use place value method, show working
• "Convert binary to denary" → Add up place values where bit = 1
• "Why use hexadecimal?" → Compact/shorter than binary, easier for humans to read
• "Convert hex to binary" → Expand each hex digit to 4 bits
• "What is a bit?" → Single binary digit (0 or 1)

Key facts to memorize:

• Binary place values: 128, 64, 32, 16, 8, 4, 2, 1
• Hex letters: A=10, B=11, C=12, D=13, E=14, F=15
• 1 hex digit = 4 binary bits (FF = 11111111)
• 8-bit binary range: 0-255 (00-FF in hex)

Common mistakes to avoid:

• Forgetting to show working - ALWAYS show place values!
• Reading remainders wrong direction in division method
• Mixing up hex letters (remember: A=10, F=15)
• Not padding to 4 bits when converting hex to binary (3 must be 0011, not 11)
• Saying "hexadecimal is faster" - NO! It's just a shorthand notation

Conversion strategy:

1. Binary → Denary: Fastest method - add place values where bit = 1
2. Denary → Binary: Use place value method (easier to show working than division)
3. Hex ↔ Binary: Use 4-bit groups (fastest method!)
4. Hex ↔ Denary: Convert via binary (hex→binary→denary) OR use multiplication/division by 16