Denary to Binary Conversion
This key facts covers Denary to Binary Conversion within Binary & Hex for GCSE Computer Science. Revise Binary & Hex in 3.3 Data Representation for GCSE Computer Science with 16 exam-style questions and 22 flashcards. This is a high-frequency topic, so it is worth revising until the explanation feels precise and repeatable. It is section 6 of 15 in this topic. Use this key facts to connect the idea to the wider topic before moving on to questions and flashcards.
Topic position
Section 6 of 15
Practice
16 questions
Recall
22 flashcards
Denary to Binary Conversion
Method 1: Place Value Method (Easiest for Exams)
Write out the place values, then work left to right deciding if each place value fits.
Example: Convert 156 to binary
Place values: 128 64 32 16 8 4 2 1
Number: 156
128 fits? YES → 1 (156 - 128 = 28 remaining)
64 fits in 28? NO → 0
32 fits in 28? NO → 0
16 fits in 28? YES → 1 (28 - 16 = 12 remaining)
8 fits in 12? YES → 1 (12 - 8 = 4 remaining)
4 fits in 4? YES → 1 (4 - 4 = 0 remaining)
2 fits in 0? NO → 0
1 fits in 0? NO → 0
Answer: 10011100
Method 2: Division Method
Repeatedly divide by 2, recording remainders from bottom to top.
Example: Convert 45 to binary
45 ÷ 2 = 22 remainder 1 ← LSB (rightmost) 22 ÷ 2 = 11 remainder 0 11 ÷ 2 = 5 remainder 1 5 ÷ 2 = 2 remainder 1 2 ÷ 2 = 1 remainder 0 1 ÷ 2 = 0 remainder 1 ← MSB (leftmost) Read remainders from bottom to top: 101101
Keep building this topic
Read this section alongside the surrounding pages in Binary & Hex. That gives you the full topic sequence instead of a single isolated revision point.
Practice Questions for Binary & Hex
Which of the following correctly describes the hexadecimal number system?
Explain why hexadecimal is used instead of binary when programmers write memory addresses and colour codes. Give three reasons.
Quick Recall Flashcards
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