.078, 7.789, 7.890,76.98
Here's your answer from the least to the greatest
1) Whenever there's a whole number before the decimal then this decimal value is greater. For e.g. 76 .98, is greater because * 76 * is bigger than the 7 in 7 .890
2)If there are no whole numbers before the decimal put the decimal values' as a fraction and compare them with the rest. You'll be able to figure which is which.