create and use variables

variable name java
https://docs.oracle.com/javase/tutorial/java/nutsandbolts/variables.html

data type variable name = initial value
int numberOfCoffees = 2;
display(numberOfCoffees);
display(numberOfCoffees * 5);

DDMS stands for Dalvik Debug Monitor Server, and is a tool in Android to help you debug your app.
https://developer.android.com/studio/profile/ddms.html?utm_source=udacity&utm_medium=course&utm_campaign=android_basics
Debug, Crashes, Compile time error, Runtime error, System log, Stacktrace

debugging android studio
https://developer.android.com/studio/debug/index.html

int quantity = 2;
quantity = 3;
quantity = 4;
quantity = 5;

int quantity = 2;
quantity = quantity + 1;