分析:(1)(2)(3)運用湊整法簡算;
(4)先把28分解7×4,再運用乘法結(jié)合律簡算;
(5)先把32分解成8×4,再運用乘法結(jié)合律簡算;
(6)運用商不變規(guī)律簡算;
(7)運用乘法結(jié)合律簡算;
(8)根據(jù)連續(xù)除以兩個數(shù),等于除以這兩個數(shù)的積簡算.
解答:解:(1)1874-298,
=1874-300+2,
=1574+2,
=1576;
(2)762+99,
=762+100-1,
=862-1,
=861;
(3)789-101,
=789-100-1,
=689-1,
=688;
(4)28×25,
=7×4×25,
=7×(4×25),
=7×100,
=700;
(5)125×32,
=125×(8×4),
=125×8×4,
=1000×4,
=4000;
(6)810÷45,
=(810÷9)÷(45÷9),
=90÷5,
=18;
(7)72×8×5,
=72×(8×5),
=72×40,
=2880;
(8)480÷6÷8,
=480÷(6×8),
=480÷48,
=10.
點評:完成本題要注意分析式中數(shù)據(jù),運用合適的簡便方法計算.