Question

用简便方法计算．12.5×4.37×0.8 13.7×4.3+13.7×5.7 28.1×0.35-0.35×8.1 &nb...

用简便方法计算．12.5×4.37×0.8 13.7×4.3+13.7×5.7 28.1×0.35-0.35×8.1 4.23×99+4.23 5.37÷0.4÷2.5 （6.3+3.9）÷0.3 7.6÷8+2.4÷8 0.42÷35．

Answer 1

①12.5×4.37×0.8
=（12.5×0.8）×4.37
=10×4.37
=43.7；

②13.7×4.3+13.7×5.7
=13.7×（4.3+5.7）
=13.7×10
=137；

③28.1×0.35-0.35×8.1
=（28.1-8.1）×0.35
=20×0.35
=7；

④4.23×99+4.23
=4.23×（99+1）
=4.23×100
=423；

⑤5.37÷0.4÷2.5 
=5.37÷（0.4×2.5）
=5.37÷1
=5.37；

⑥（6.3+3.9）÷0.3
=6.3÷0.3+3.9÷0.3
=21+13
=34；

⑦7.6÷8+2.4÷8 
=（7.6+2.4）÷8
=10÷8
=1.25；

⑧0.42÷35
=0.42÷7÷5
=0.06÷5
=0.012．