解:(1)×59 | =×(60-1), |
=
×60-
,
=19-
,
=18
;
(2)1
-(
+
)
=1
-
-
,
=1-
,
=
;
(3)0.125×0.25×8×4
=(0.125×8)×(0.25×4),
=1×1,
=1;
(4)87.7×11-87.7
=(11-1)×87.7,
=10×87.7,
=877;
(5)4÷1.25÷0.8
=4÷(1.25×0.8),
=4÷1,
=4;
(6)8.05-0.75-
=8.05-(0.75+0.25),
=8.05-1,
=7.05.
分析:(1)可根據(jù)湊整法將原式變?yōu)?img class='latex' src='http://thumb.zyjl.cn/pic5/latex/204543.png' />×(60-1)后,再根據(jù)乘法分配律計(jì)算;
(2)可根據(jù)一個數(shù)減兩個數(shù)的和,等于用這個數(shù)減去兩數(shù)中的被減數(shù)加上減數(shù)的減法性質(zhì)計(jì)算;
(3)可根據(jù)乘法交換律及結(jié)合律計(jì)算;
(4)可根據(jù)乘法分配律計(jì)算;
(5)可根據(jù)一個數(shù)除以兩個數(shù),等于用這個數(shù)除以這兩個數(shù)的積的除法性質(zhì)計(jì)算;
(6)可根據(jù)一個數(shù)減兩個數(shù),等于用這個數(shù)減去這兩個數(shù)的和的減法性質(zhì)計(jì)算.
點(diǎn)評:完成本題要注意分析題目中數(shù)據(jù)的特點(diǎn),然后運(yùn)用合適的方法計(jì)算.