Numbers, such as 784, have three digits.  Each digit is a different place value.  

The first digit is called the hundreds' place.  It tells you how many sets of one hundred are in the number.  The number 784 had seven hundreds. 

The middle digit is the tens' place.  It tells you that there are 8 tens in addition to the seven hundreds. 

The last or right digit is the ones' place which is 4 in this example.  Therefore, there are 7 sets of 100, plus 8 sets of 10, plus 4 ones in the number 784.

  7 8 4
  | | |__ones' place
  | |_________tens' place
  |________________hundreds' place