Answer:
3.021, 3.21, 3.121, 3.12
Step-by-step explanation:
Ordering Decimals
1. Set up a table with the decimal point in the same place for each number.
2. Put in each number.
3. Fill in the empty squares with zeros.
4. Compare using the first column on the left.
5. If the digits are equal move to the next column to the right until one number wins.