How do you XOR hexadecimal values? Calculate: $\mathtt{A7} \oplus \mathtt{3C}$

Convert each hex digit to 4-bit binary, XOR the bits, then convert back to hex. Result: $\mathtt{9B}$.

$$\begin{aligned} \mathtt{A7}_{16} &= 1010\,0111 \\ \mathtt{3C}_{16} &= 0011\,1100 \\ \mathtt{A7} \oplus \mathtt{3C} &= 1001\,1011 = \mathtt{9B}_{16} \end{aligned}$$

Method:

1. Convert each hex digit to its 4-bit nibble (A=1010, 7=0111, 3=0011, C=1100)
2. XOR the binary representations bit by bit
3. Convert the result back to hex (1001=9, 1011=B)

Tip: With practice, you can XOR hex digits directly by memorizing common pairs, but converting to binary is always reliable.