分析:(1)按照從左到右的順序計(jì)算,不要錯(cuò)用了運(yùn)算定律;
(2)先算乘法,再算減法;
(3)根據(jù)減法的性質(zhì)簡算;
(4)運(yùn)用乘法交換律簡算;
(5)先除法,再算加法;
(6)先算小括號(hào)里面的減法,再算括號(hào)外的乘法;
(7)運(yùn)用加法交換律簡算;
(8)根據(jù)除法的性質(zhì)簡算.
解答:解:(1)100-28+72,
=72+72,
=144;
(2)200-28×5,
=200-140,
=60;
(3)297-28-72,
=297-(28+72),
=297-100,
=197;
(4)4×89×25,
=4×25×89,
=100×89,
=8900;
(5)54+783÷27,
=54+29,
=83;
(6)40×(62-37),
=40×25,
=1000;
(7)78+99+22,
=78+22+99,
=100+99,
=199;
(8)900÷25÷4,
=900÷(25×4),
=900÷100,
=9.
點(diǎn)評(píng):本題考查了四則混合運(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)算定律進(jìn)行簡便計(jì)算.