Example expressions which works with this applet:
(2+(2*3)+6)                                          = 14.0

(((5+((10/2)+5)*6)/2)*(15-5))/(10*10)                = 3.25

(((2+(10/2)+6)*(2))+(10+(2*3)))*(-1/2)		     = -21.0

(2+(2+3)+6*(4+3))                                    = 49.0

(2+(2+3)+6*(10))+((4+(25-2)*2))                      = 117.0

(2+(2+3)+6*(10))+(3+(10-3)*(11))                     = 147.0

((2+3)+6*(10))/(5)                                   = 13.0

(1+10/2-2)+(4+5)-(14)                                = -1 (prefered input)

(94.8+14.2*94.8)+(24.3*36.9/79.3)                    = 1450.0 (prefered input)

(1+10/2-2)+(4+5)/(4+24/8)-(1+10/2-2)+(4+5)*(4+24/8)  = -61.7 (prefered input)

(2--8*2)                                             = 18.0

(-2*4+-4)                                            = -12.0

(2+(2--8*2)+6*(-2*4+-4))                             = -52.0