分析:算式(1)可根據(jù)乘法結(jié)合律計算;
算式(2)可根據(jù)乘法交換律計算;
算式(3)可根據(jù)乘法分配律計算;
算式(4)可根據(jù)乘法分配律計算中括號中的算式.
解答:解:(1)1.2-0.5×1.8÷0.9
=1.2-0.5×(1.8÷0.9),
=1.2-0.5×2,
=1.2-1,
=0.2;
(2)8×7×1.25
=8×1.25×7,
=10×7,
=70;
(3)
×8.8+1.2×
+60%,
=0.6×8.8+1.2×0.6+0.6,
=(1.2+8.8)×06+0.6,
=10×0.6+0.6,
=6+0.6,
=6.6.
(4)[15×(50%+
)]÷
,
=[15×0.5+15×
]×
,
=[7.5+5]×
,
=12.5×
,
=20.
點評:當(dāng)算式中同時含有分?jǐn)?shù)、小數(shù)或百分?jǐn)?shù)時,要根據(jù)式中數(shù)據(jù)的特點靈活將它們互化后再進(jìn)行計算.