簡便計(jì)算
108×125
266+45+34
273×104-273×4
572-183-17
4700÷4÷25.
解:(1)108×125
=(100+8)×125,
=100×125+8×125,
=12500+100,
=13500;
(2)266+45+34
=266+34+45,
=300+45,
=345;
(3)273×104-273×4
=(104-4)×273,
=100×273,
=27300;
(4)572-183-17
=572-(183+17),
=572-200,
=372;
(5)4700÷4÷25
=4700÷(4×25),
=4700÷100,
=47.
分析:(1)可將108拆分為100+8后根據(jù)乘法分配律計(jì)算;
(2)可根據(jù)加法交換律計(jì)算;
(3)可根據(jù)乘法分配律計(jì)算;
(4)可根據(jù)一個(gè)數(shù)減兩個(gè)數(shù)等于用這個(gè)數(shù)減去兩個(gè)數(shù)的積的減法性質(zhì)計(jì)算;
(5)可根據(jù)一個(gè)數(shù)除以兩個(gè)數(shù),等于除以這兩個(gè)數(shù)的和的除法性質(zhì)計(jì)算.
點(diǎn)評(píng):完成本題要注意分析式中數(shù)據(jù)的特點(diǎn)及內(nèi)在聯(lián)系,然后運(yùn)用合適的方法進(jìn)行計(jì)算.