The IDENTITY for an operation is the number that causes no change
when you use it under that operation.

Example 1:

0 is the identity for ADDITION, because it is the only number that
causes no change in a number when you ADD 0 to it.

When you add 0 to 3 you get 3, which means that you have not changed
the 3 by ADDING 0 to it. 

When you add 0 to 7 you get 7, which means that you have not changed
the 7 by ADDING 0 to it.

When you add 0 to ANY NUMBER you get THAT SAME NUMBER, which means that 
you have not changed that number by adding 0 to it.

Example 2:

1 is the identity for MULTIPLICATION, because it is the only number that
causes no change in a number when you MULTIPLY it by 1.

When you MULTIPLY 3 by 1 you get 3, which means that you have not changed
the 3 by MULTIPLYING it by 1. 

When you MULTIPLY 7 by 1 you get 7, which means that you have not changed
the 7 by MULTIPLYING it by 1.

When you MULTIPLY ANY NUMBER by 1 you get THAT SAME NUMBER, which means that
you have not changed the number by MULTIPLYING it by 1.

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So you use the identity property of ADDITION every time you ADD 0 to a number 
and get the same number back.

And you use the identity property of MULTIPLICATION every time you MULTIPLY a
number by 1 and get the same number back. 

Edwin