How to represent -1 as a byte I want to initialize the value of byte to -1. When I just use byte num = -1 the value ends up being a decimal 255. I've also tried int8_t number = -1 and then byte num = number but this didn't work either.
A byte can't be -1. A byte can only store numbers between 0 and 255 inclusive.

Depending on the range of your numbers you could use a char (-128 to +127) or an int (-32768 to +32767).