考點:運算定律與簡便運算
專題:運算定律及簡算
分析:(1)把296看作300-4,簡算即可;
(2)把1001看作1000+1,運用乘法分配律簡算;
(3)把25看作5×5,運用除法的運算性質簡算;
(4)把24看作8×3,運用乘法結合律簡算;
(5)運用減法的性質簡算;
(6)運用乘法交換律與結合律簡算;
(7)運用乘法分配律簡算;
(8)先算括號內的,原式變?yōu)?08×1100+712,再把1100看作1000+100,運用乘法分配律簡算.
解答:
解:(1)563+296
=563+(300-4)
=863-4
=859
(2)1001×78
=(1000+1)×78
=1000×78+78
=78000+78
=78078
(3)4500÷25
=4500÷(5×5)
=4500÷5÷5
=900÷5
=180
(4)125×24
=(125×8)×3
=1000×3
=3000
(5)1846-620-380
=1846-(620+380)
=1846-1000
=846
(6)8×125-25×6×4
=1000-(25×4)×6
=1000-600
=400
(7)32×46+32×54
=32×(46+54)
=32×100
=3200
(8)408×(3080-1980)+712
=408×1100+712
=408×(1000+100)+712
=408×1000+408×100+712
=408000+40800+712
=449512
點評:完成本題要注意分析式中數(shù)據(jù),選用合適的簡便方法計算.