怎樣算簡(jiǎn)便就怎樣算.
5.3+8.44+4.7+1.56
400-(1300÷65+35)
15.35-(5.35+3.88)
29×46-46×19
87×102
6.78-3.86+0.92.
解:(1)5.3+8.44+4.7+1.56,
=(5.3+4.7)+(8.44+1.56),
=10+10,
=20;
(2)400-(1300÷65+35),
=400-(20+35),
=400-55,
=345;
(3)15.35-(5.35+3.88),
=15.35-5.35-3.88,
=10-3.88,
=6.12;
(4)29×46-46×19,
=46×(29-19),
=46×10,
=460;
(5)87×102,
=87×(100+2),
=8700-174,
=8526;
(6)6.78-3.86+0.92,
=2.92+0.92,
=3.84.
分析:(1)運(yùn)用加法交換律和結(jié)合律簡(jiǎn)算;
(2)先算括號(hào)內(nèi)的除法,再算括號(hào)內(nèi)的加法,最后算括號(hào)外的減法;
(3)運(yùn)用減法的性質(zhì)簡(jiǎn)算;
(4)運(yùn)用乘法發(fā)分配律簡(jiǎn)算;
(5)把102看作(100+2),運(yùn)用乘法發(fā)分配律簡(jiǎn)算;
(6)按運(yùn)算順序從左向右依次計(jì)算.
點(diǎn)評(píng):此題考查了小數(shù)、整數(shù)的四則混合運(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)算律簡(jiǎn)便計(jì)算