考點(diǎn):運(yùn)算定律與簡便運(yùn)算
專題:運(yùn)算順序及法則
分析:(1)根據(jù)加法的交換律和連減的簡便方法計(jì)算即可;
(2)根據(jù)減法的性質(zhì),計(jì)算即可;
(3)98=100-2,然后去括號(hào),計(jì)算即可;
(4)102=100+2,去括號(hào),計(jì)算即可;
(5)(6)(7)(8)(9)根據(jù)加法的交換律和連減的簡便方法計(jì)算即可;
(10)303=300+3,然后去括號(hào),計(jì)算即可;
(11)405=400+5,然后去括號(hào),計(jì)算即可;
(12)根據(jù)減法的性質(zhì),計(jì)算即可;
(13)根據(jù)加法的交換律和連減的簡便方法計(jì)算即可;
解答:
解:(1)35+27+65
=(35+65)+27
=100+27
=127
(2)872-481-219
=872-(481+219)
=872-700
=172
(3)316-98
=316-(100-2)
=316-100+2
=218
(4)157+102
=157+(100+2)
=157+100+2
=259
(5)272+125+75+28
=(272+28)+(125+75)
=300+200
=500
(6)175-57-43+25
=(175+25)-(57+43)
=200-100
=100
(7)91+89+11
=91+(89+11)
=91+100
=191
(8)85+41+15+18
=(85+15)+(41+18)
=100+59
=159
(9)282+53+37+18
=(282+18)+(53+37)
=300+90
=390
(10)721-303
=721-(300+3)
=721-300-3
=421-3
=418
(11)900-405
=900-(400+5)
=900-400-5
=500-5
=495
(12)435-(135+189)
=435-135-189
=300-189
=111
(13)11+13+15+17+19
=(11+19)+(13+17)+15
=30+30+15
=75
點(diǎn)評(píng):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)算律簡便計(jì)算.