Negative Numbers

Two’s complement

An interactive lesson with 6 steps, about 5 minutes: you predict, drag and solve, with instant feedback on every answer. It runs in your browser and needs JavaScript.

What you’ll learn

• Two’s complement: the top bit is worth −2ⁿ⁻¹.
• Negate by flipping all bits and adding 1; addition works unchanged.
• Exceeding the range overflows and wraps around.

Steps

1. Where’s the minus sign?
2. Make −5
3. Flip and add one
4. The range
5. Overflow
6. Gangnam Style