1.計(jì)算下面各題,(能簡(jiǎn)算的要簡(jiǎn)算)
72×99.9
8.65-(2.65+1.79)
59÷518+1318×95
[78-(516-14)]÷2627
5020-2940÷28×37
(27+15)×7×5.
分析 (1)把99.9看作100-0.01,再根據(jù)乘法分配律進(jìn)行計(jì)算即可;
(2)根據(jù)減法的性質(zhì)進(jìn)行計(jì)算即可;
(3)先算乘法和除法,再算加法;
(4)先算小括號(hào)里的減法,再算中括號(hào)里的減法,最后算除法;
(5)先算除法和乘法,再算減法;
(6)根據(jù)乘法分配律進(jìn)行計(jì)算即可.
解答 解:(1)72×99.9
=72×(100-0.01)
=72×100-72×0.01
=7200-0.72
=7199.28;
(2)8.65-(2.65+1.79)
=8.65-2.65-1.79
=6-1.79
=4.21;
(3)59÷518+1318×95
=59×185+1318×95
=2+1310
=3310;
(4)[78-(516-14)]÷2627
=[78-116]÷2627
=1316÷2627
=2732;
(5)5020-2940÷28×37
=5020-105×37
=5020-3885
=1135;
(6)(27+15)×7×5
=27×7×5+15×7×5
=10+7
=17.
點(diǎn)評(píng) 考查了分?jǐn)?shù)四則混合運(yùn)算與簡(jiǎn)便運(yùn)算,注意運(yùn)算順序和運(yùn)算方法,靈活運(yùn)用運(yùn)算定律進(jìn)行簡(jiǎn)算.