考點(diǎn):整數(shù)四則混合運(yùn)算,運(yùn)算定律與簡(jiǎn)便運(yùn)算,分?jǐn)?shù)的四則混合運(yùn)算,小數(shù)四則混合運(yùn)算
專題:運(yùn)算順序及法則,運(yùn)算定律及簡(jiǎn)算
分析:(1)先算除法,再算乘法,最后算減法;
(2)(4)利用乘法分配律簡(jiǎn)算;
(3)利用加法交換律與減法的性質(zhì)簡(jiǎn)算;
(5)先算括號(hào)里面的除法,再算里面的減法,最后算括號(hào)外面的除法;
(6)任填兩數(shù),最好兩數(shù)之和是整十整百,整千數(shù).再利用乘法分配律簡(jiǎn)算.
解答:
解:(1)690-630÷6×5
=690-105×5
=690-525
=165;
(2)
×101
=
×(100+1)
=
×100+
×1
=
63;
(3)14.32-7.8+1.68-3.2
=14.32+1.68-(7.8+3.2)
=16-11
=5;
(4)36×(
+
-
)
=36×
+36×
-36×
=3+30-27
=6;
(5)(30-24.6÷1.2)÷0.01
=(30-20.5)÷0.01
=9.5÷0.01
=950;
(6)32×
+8÷
=32×
+8×
=(32+8)×
=40×
=300.
點(diǎn)評(píng):四則混合運(yùn)算的關(guān)鍵是抓住運(yùn)算順序,正確按運(yùn)算順序計(jì)算,適當(dāng)運(yùn)用運(yùn)算定律簡(jiǎn)算.