Subtracting an integer from an ASCII number
It depends how exactly you do the subtraction. Depending on the processor, the string 10 is either 0x3031 (little endian) or 0x3130 (big endian). Most modern processors are little endian. That's assuming you regard 10 as a 16-bit integer, i.e. a C short on modern computers. If you're regarding it as a C char, then only the first digit 1 will be affected.