Binary Subtraction
1. **State the problem:** We need to subtract the binary number $(011100)_2$ from $(0101101)_2$ using the complementary method.
2. **Convert both numbers to the same bit length:**
- $(0101101)_2$ has 7 bits.
- $(011100)_2$ has 6 bits, so we add a leading zero to make it 7 bits: $(0011100)_2$.
3. **Find the 2's complement of the subtrahend $(0011100)_2$:**
- First, find the 1's complement by flipping each bit:
$$0011100 \to 1100011$$
- Then add 1 to get the 2's complement:
$$1100011 + 1 = 1100100$$
4. **Add the 2's complement of the subtrahend to the minuend:**
$$0101101 + 1100100 = 10010001$$
5. **Check for overflow:**
- Since we are working with 7-bit numbers, the 8th bit (leftmost) is an overflow bit.
- Discard the overflow bit, leaving us with:
$$0010001$$
6. **Interpret the result:**
- The result is positive because there was an overflow bit.
- Convert $0010001_2$ to decimal:
$$0\times2^6 + 0\times2^5 + 1\times2^4 + 0\times2^3 + 0\times2^2 + 0\times2^1 + 1\times2^0 = 16 + 1 = 17$$
7. **Verify by decimal subtraction:**
- $(0101101)_2 = 45$ decimal
- $(011100)_2 = 28$ decimal
- $45 - 28 = 17$, which matches our binary result.
**Final answer:**
$$\boxed{0010001_2}$$ which equals 17 in decimal.