Hexadecimal: How does FF = 255?

[dblue]

Decimal is base 10
Hexadecimal is base 16

0x0F = 15
0x10 = 16
0x11 = 17
…
0x1F = 31
0x20 = 32
0x21 = 33
…
0x7F = 127
0x80 = 128
0x81 = 129
…
0xFF = 255
0x100 = 256

And so on…

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