76+5= 78+3= 72+9= 77+7=
5x-12.5=2 3×(2x+7)=45 5.6-4x=3.2
(13×0.58-4.87+0.42×13- 5.13) ×4.25
999×778+333×666
-(+)
0.5×1.6+0.5×26.4