(3.5+2.5)×=3.5×+×4
4.87×99=4.87×(-)
5.2×10.1 1.25×6.7×0.8
1.45×7.5+0.55×7.5 2.43×5.2+2.43×4.8
①0.53×2.5+
②25×0.032×12.5
③ [()×]
④6.83+17.9﹣0.83+32.1
①25×32×1.25
②(+0.375)÷(×)
③×+÷7
④6﹣(+)
①7.4﹣6.62+20.6﹣13.38
②×+×
③(-+)÷
④2×0.8×12.5×50%
⑤÷(÷+)
⑥×[1÷(+)]