Question

【題目】用簡(jiǎn)便方法計(jì)算下面各題．

0.75+++0.375

356×+420÷+

（+）÷

32.48﹣（39.5+2.48）

Answer 1

【答案】①0.75+++0.375=2

②356×+420÷+=666

③（+）÷=25

④32.48﹣（39.5+2.48）=﹣9.5

【解析】

試題分析：①把分?jǐn)?shù)化成小數(shù)，根據(jù)加法交換律及結(jié)合律計(jì)算；

②420÷=420×，根據(jù)乘法分配律進(jìn)行計(jì)算；

③除以，等于乘4，再根據(jù)乘法分配律進(jìn)行計(jì)算；

④根據(jù)減法性質(zhì)進(jìn)行計(jì)算．

解：①0.75+++0.375

=0.75+0.625+0.25+0.375

=（0.75+0.25）+（0.625+0.375）

=1+1

=2

②356×+420÷+

=356×+420×+

=（356+420+1）×

=777×

=666

③（+）÷

=（+）×24

=×24+×24

=9+16

=25

④32.48﹣（39.5+2.48）

=32.48﹣39.5﹣2.48

=32.48﹣2.48﹣39.5

=﹣9.5