It doesn't matter !

$0:=48, 9:=57, A:=65, Z:=90, a:=\boxed{?}, z:=122$ 1. In Logic perspective we see that:

• There are $10$ integers from 0 to 9 both inclusive. Similarly, there are $10$ integers from 48 to 57 both inclusive.

• There are $26$ English alphabets from A to Z both inclusive. Similarly, there are $26$ integers from 65 to 90 both inclusive.

Therefore, since there are $26$ English alphabets from a to z both inclusive. Similarly, there are $26$ integers from $\boxed{?}$ to 122 both inclusive. It implies that $\boxed{?}=122-26+1=123-26=97$ or $\boxed{?}=\boxed{97}$ . $$ 2. In Computer Science perspective we see that:

• 48 is an ASCII value of '0' in decimal form

• 57 is an ASCII value of '9' in decimal form

• 65 is an ASCII value of 'A' in decimal form

• 90 is an ASCII value of 'Z' in decimal form

• $\boxed{?}$ is an ASCII value of 'a' in decimal form

and

• 122 is an ASCII value of 'z' in decimal form

Therefore:

• $\boxed{97}$ is an ASCII value of 'a' in decimal form.