Baud rate refers to the speed at which data is sent & received over the serial connection. In your Arduino sketch it’s usually set in the setup routine with something like "Serial.begin(9600);" (without the quotes). Whatever speed (in this case 9600 baud) you use, it must then be matched in your Max patch as an argument to the serial object: [serial b 9600].
Also, if you are getting the correct value in Arduino serial monitor, you will need to convert ASCII to integers when receiving them in Max, or else send from Arduino as integers rather than ASCII (i.e., using serial.write instead of serial.print).
