The powers of Ten
Our number system is base 10. It is known as the Base Ten Positional System because each digit level or position is larger than the one before it by one power of ten. Positions to the left of the decimal point make up the whole number part of the digit. Note: If no decimal point is visible, we assume it is behind the last number. For example, The number 3 written with a decimal point would be 3.0.
The graphic below shows the progression of place values on the whole number (left) side or real numbers.
Digit Levels or Positions
Decimal Place Values
Similarly, decimal places vary by negative powers of ten. The portion of a number to the right of the decimal point is known as the fractional or decimal part. Examine the graphic below:
Decimal Levels or Positions