Subtracting binary numbers uses the same borrowing concept as decimal. When you subtract a larger digit from a smaller one, borrow from the next column.
Rules: , , , requires borrowing (borrow 1 from next column, making it ). Example: . Work right to left with borrowing as needed. Result: .
Computers rarely use subtraction directly. Instead, they add negative numbers using two's complement. This unifies addition and subtraction into one circuit, saving hardware. Let me show you how that works.