看一看，填一填。12-4= 13-4= 14-4=
5x-12.5=23×(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
3×(2x+7)=45 5.6-4x=3.2
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+
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