You do not change the identity of whatever you are working with.
*Add zero to it and you still get the same number as your answer
Ex: a+0=a or 5+0=5
Adding a number with the opposite of that number (such as negative or positive) makes it into a zero.
Ex: 5+ -5 = 0
Adding the two same numbers while having the SAME ANSWER on both sides of the equal sign.
Ex: a+b=b+a or 3+4=4+3
What numbers are getting associated with what numbers (You should get the same answer on both sides of the equal sign)