1.1 · Lesson 4 of 6
Binary addition and overflow
Syllabus 1.1.4
What this lesson covers
- Add two 8-bit binary integers and recognise overflow
Key vocabulary
- Binary addition
- Adding binary numbers column by column from right to left, using the 4 rules.
- Carry
- A 1 moved into the next column to the left when a column adds up to 2 or 3.
- Register
- A small, fast store in the CPU with a fixed size, e.g. 8 bits, that holds data being processed.
- Overflow error
- Happens when the result of a calculation is too large to fit in the register, e.g. more than 255 in 8 bits.
- Most significant bit (MSB)
- The leftmost bit in a binary number, with the highest place value.
- Least significant bit (LSB)
- The rightmost bit in a binary number, with the lowest place value. Addition starts here.
Check your learning
- Quick check: 4 questions
- Key vocabulary test: 6 terms
- Activity 1: Binary addition · 10 questions
- Activity 2: Spot the overflow · 5 questions
- Activity 3: Binary addition quiz · 8 questions