Ask some problem about rotation, quaternion and angle

Hi everyone, First, I am sorry because bad english. I am a new guy and have some problem with rotation in unity (unity version 5.2.2f1) win8.1. I have object (about 20 childs with rigidbody, sphere collider, box collider ect...) and i want to rotate it. I use code: transform.localRotation = Quaternion.Euler (new Vector3 (-90, 0, 180)); but the number of angle in editor is (X,Y,Z) = (270,180,0). I tried by fix it in editor, changed by hand in editor X = -90, Y = 0, Z = 180 but after enter, it changed to (X,Y,Z) = (270,180,0). How can i fix it? Thank you in advance !