考點(diǎn):小數(shù)四則混合運(yùn)算
專題:運(yùn)算順序及法則
分析:①③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.
②可先將題目中的分?jǐn)?shù)、百分?jǐn)?shù)化成小數(shù)后,根據(jù)乘法分配律計(jì)算.
④可根據(jù)乘法分配律計(jì)算.
解答:
解:①(5-4.75)÷(2×2.5-3);
=0.25÷(5-3)
=0.25÷2
=0.125;
②22×
+25×75%-7×0.75
=22×0.75+25×0.75-7×0.75
=(22+25-7)×0.75
=40×0.75
=30;
③
÷(1-
×0.4)
=
÷(1-0.3)
=0.7÷0.7
=1;
④1100+56×(
-
)
=1100+56×
-56×
=1100+24-21
=1103.
點(diǎn)評(píng):當(dāng)算式中同時(shí)含有分?jǐn)?shù)、百分?jǐn)?shù)、小數(shù)時(shí),一般要先將它們化成統(tǒng)的一數(shù)據(jù)形式后,再進(jìn)行計(jì)算.