Hello,
I have 2 connected Arduino (nano with ATmega328 ) and i want that the 1st one generate and use an integer and give the value to the 2nd one.
I hope you understand my question 
and thanks for your answere 
Connect them up via their serial ports & Gnd.
The sender uses Serial.write() to send the data, the receiver uses Serial.available() to see if data came in, and then Serial.read() to read it.
Thank you for the helpful and fast answer. 