Decimal numbers, such as O.6495, have four digits after the decimal point.  Each digit is a different place value.  

The first digit after the decimal point is called the tenths place value. There are six tenths in the number O.6495.

The second digit tells you how many hundredths there are in the number.  The number O.6495 has four hundredths. 

The third digit is the thousandths place. 

The fourth digit is the ten-thousandths place which is five in this example. 

Therefore, there are six tenths, four hundredths, nine thousandths, and five ten-thousandths in the number 0.6495.