Order the following numbers from least to greatest.

7–√ , −2.3 , 3–√ , 5.1 , −13

−13, −2.3, 7–√, 3–√, 5.1

To order the numbers from least to greatest, we will need to compare them:

1. Start by comparing the negative values:
-13 < -2.3

Order so far: -13, -2.3

2. Next, compare the square root values:
7–√ < 3–√

Order so far: -13, -2.3, 7–√

3. Finally, compare the remaining positive decimal values:
7–√ < 5.1

Final order: -13, -2.3, 7–√, 5.1

Therefore, the numbers from least to greatest are: -13, -2.3, 7–√, 5.1.