Question

3．下面各題怎樣算簡便就怎樣算
0.63×99+0.63                                       4.4×12.5
7.5+2.5×6.4                                        5.5×0.8-4.5×0.6．

Answer 1

分析 （1）根據(jù)乘法分配律簡便計(jì)算；
（2）變形為1.1×（4×12.5）計(jì)算；
（3）變形為7.5+2.5×4×1.6計(jì)算；
（4）先算乘法，再算減法．

解答 解：（1）0.63×99+0.63
=0.63×（99+1）
=0.63×100
=63 
（2）4.4×12.5
=1.1×（4×12.5）
=1.1×50
=55
（3）7.5+2.5×6.4
=7.5+2.5×4×1.6
=7.5+10×1.6
=7.5+16
=23.5
（4）5.5×0.8-4.5×0.6
=4.4-2.7
=1.7

點(diǎn)評 考查了運(yùn)算定律與簡便運(yùn)算，四則混合運(yùn)算．注意運(yùn)算順序和運(yùn)算法則，靈活運(yùn)用所學(xué)的運(yùn)算定律簡便計(jì)算．