place value
Numbers, such as 84, have two digits. Each digit is a different place value.
The left digit is the tens' place. It tells you that there are 8 tens in the number.
The last or right digit is the ones' place which is 4 in this example. Therefore, there are 8 sets of 10, plus 4 ones in the number 84.
8 4
| |__ones' place
|_________tens' place