1/6 u * 6 = u
3x * 1/3 = x
-5y * 3/5 = -3y
0,9z : 3 = 0,3z
-3/7 w : 3/7 = -w
5x * 4 = 20x
-8y : (-8) = y
-10z : (-5) = 2z
1/4 u * 4 = u
-1/5 v * (-5) = v