To order the numbers 4.397, 4.4, and 4.38 from least to greatest, we can compare them:
- 4.38 is the smallest because it is equivalent to 4.380, which is less than both 4.397 and 4.4.
- 4.397 is next, as it is greater than 4.38 but less than 4.4.
- 4.4 is the largest.
Thus, the order from least to greatest is: 4.38, 4.397, 4.4.
The smallest number is: 4.38.