First simplify each absolute value expression to get....
|-7.18| = 7.18
|7.15| = 7.15
|-7.21| = 7.21
|-7.09| = 7.09
|6.99| = 6.99
Keep in mind that absolute value results are always positive (assuming the input isn't 0, in which case the result is 0)
The sorted values from smallest (least) to largest (greatest) is this list
6.99, 7.09, 7.15, 7.18, 7.21
So the proper order of the expressions is
|6.99|, |-7.09|, |7.15|, |-7.18|, |-7.21|