In the operation of addition there is a "do nothing" number, 0, which means
that if you add it to any other number, or add any number to it, you will get
that same number as the answer.  That is, it does nothing to add 0.  The "do
nothing" number 0, for addition, is called "the additive identity". 

In multiplication there is also a "do nothing" number, 1, which means that 
if you multiply it by any other number, or multiply any number by it, you will
get that same number as the answer.  That is, it does nothing to multiply by
1.  The "do nothing" number 1, for multiplication, is called 
"the multiplicative identity".

This equation

x*1=x

shows that when you multiply x by 1 you get the same number x that you started
with.  1 is the "do nothing" number for multiplication.  Therefore we say that
the above equation demonstrates: 

the identity property of multiplication

Edwin