Place value columns
Every digit has a value set by the column it sits in — to the left or right of the decimal point.
Place value is the rule that gives each digit its size. In the does not mean four; it means four hundreds, because of the column it sits in.
For whole numbers the columns to the left of the decimal point are ones, tens, hundreds, thousands, and so on — each one ten times the one to its right. For decimals the columns continue to the right of the point: tenths (), hundredths (), thousandths (). Each step right divides by 10.
To compare decimals like and , give them the same number of decimal columns first: versus . Now compare digit by digit — . The trick is never to count the digits and assume more digits means bigger.
- Each column is ten times the one on its right.
- Decimal columns continue with tenths, hundredths and thousandths.
- The value of a digit is the digit multiplied by its column value.
- Compare decimals by lining up the decimal points.