73 - 64 = 9
9 - 8 = 1

0100 1001

2^2 + 2^3 + 2^0
4     9
0x49


-5

0000 0000
0000 0101
1111 1011

8 + 4 + 2 + 1 = F
8 + 2 + 1     = B

0xFB

0b 1101 0110
2 + 4 + 16 + 64 + 128 = 

0xD6