下面各題怎樣簡(jiǎn)便就怎樣計(jì)算
(1)12.64-(3.96+4.64)
(2)36.26-4.78+3.74
(3)7.34+7.57+12.66+6.43
(4)78.65-23.12-14.88.
解:(1)12.64-(3.96+4.64),
=12.64-3.96-4.64,
=12.64-4.64-3.96,
=8-3.96,
=4.04;
(2)36.26-4.78+3.74,
=36.26+3.74-4.78,
=40-4.78,
=35.22;
(3)7.34+7.57+12.66+6.43,
=(7.34+12.66)+(7.57+6.43),
=20+14,
=34;
(4)78.65-23.12-14.88,
=78.65-(23.12+14.88),
=78.65-38,
=40.65.
分析:(1)運(yùn)用減法的性質(zhì)以及加法交換律簡(jiǎn)算;
(2)運(yùn)用加法交換律簡(jiǎn)算;
(3)運(yùn)用加法交換律、結(jié)合律簡(jiǎn)算;
(3)運(yùn)用減法的性質(zhì)簡(jiǎn)算.
點(diǎn)評(píng):完成本題要注意分析式中數(shù)據(jù),運(yùn)用合適的簡(jiǎn)便方法計(jì)算.