分析:算式(1)要先算乘法再算加法;
算式(2)可根據(jù)一個(gè)數(shù)一個(gè)數(shù)再加上另一個(gè)數(shù),等于減去這兩個(gè)數(shù)的差的減法性質(zhì)計(jì)算;
算式(3)根據(jù)四則混合運(yùn)算的運(yùn)算順序計(jì)算即可,先算乘除,再算加減,有括號(hào)的要先算括號(hào)里面的;
算式(1)可先根據(jù)分?jǐn)?shù)除法的計(jì)算法則將式中的除法算式變?yōu)槌朔ㄋ闶胶笤俑鶕?jù)乘法分配律計(jì)算.
解答:解:(1)0.25×
+2.5%
=0.2+0.025,
=0.225;
(2)9.6-11÷7+
×4
=9.6-(
-
),
=9.6-1,
=8.6;
(3)12×[(
-
)×3]
=12×[
×3],
=12×
,
=42;
(4)5.125×
+2.875÷4,
=5.125×
+2.875×
,
=(5.125+2.875)×
,
=8×
,
=2.
點(diǎn)評(píng):當(dāng)算式中同時(shí)含有分?jǐn)?shù),小數(shù)或百分?jǐn)?shù)時(shí),一般要將它們化為統(tǒng)一的數(shù)據(jù)形式后再進(jìn)行計(jì)算.