Binary to ASCII using logical operations I am learning Computer Architecture from Introduction to Computing Systems (2nd Edition) and am stuck on this question. 

What operations can be used to convert the binary representation of 3 into ASCII representation for 3? What about binary 4 to ASCII or any other digit? 

The concepts I have learnt until now are Basic Logic gates and Bit Masking so I have to use them for conversion. Can someone help me understand what my approach should be?
By looking at a ASCII table you can see that the $4$ least significant bits of all characters between $0$ and $9$ correspond to the respective integer representations of the numbers between $0$ and $9$, while the 4 most significant bits are always $0011$ (leading zeroes are not shown in the table, so keep in mind you need to pad binary numbers to 8 bits).

If $x$ is the binary representation of a number between $0$ and $9$, you can then obtain the ASCII representation of the corresponding character as
$$
x \;| \;00110000,
$$

where $|$ denotes a bitwise logical or and the second operand is in binary.