考點(diǎn):分?jǐn)?shù)的巧算,運(yùn)算定律與簡(jiǎn)便運(yùn)算,分?jǐn)?shù)的簡(jiǎn)便計(jì)算,分?jǐn)?shù)的四則混合運(yùn)算,小數(shù)四則混合運(yùn)算,解比例
專題:運(yùn)算順序及法則,運(yùn)算定律及簡(jiǎn)算,計(jì)算問題(巧算速算)
分析:①運(yùn)用連減的性質(zhì)解答即可.
②運(yùn)用等式的性質(zhì)解答即可.
③運(yùn)用乘法分配律計(jì)算中括號(hào)里的.
④根據(jù)四則運(yùn)算法則計(jì)算即可.
⑤運(yùn)用乘法分配律計(jì)算即可.
⑥運(yùn)用比例的性質(zhì),化為方程后再運(yùn)用等式的性質(zhì)解答即可.
⑦把原式變形后,逆用乘法分配律即可.
⑧先去括號(hào),再逆用乘法分配律即可.
解答:
解:①5.33-2.45-1.55
=5.33-(2.45+1.55)
=5.33-4
=1.33
②2.75-5x=2.7
2.75-5x+5x=2.7+5x
2.75-2.7=2.7-2.7+5x
0.05=5x
x=0.01
③
÷[
×(
+
)]
=
÷(
×
+
×
)
=
÷
=
④
×
+
÷
=
+
=
⑤(
+
+
)×36
=
×36+
×36+
×36
=9+6+20
=35
⑥
:
=x:9
x=
×9
x
÷=6
÷x=
⑦4.7×15+96×1.5-0.43×150
=4.7×15+9.6×15-4.3×15
=(4.7+9.6-4.3)×15
=10×15
=150
⑧(1+
)+(2+
×2)+(3+
×3)+…+(11+
×11)
=1+
+2+
×2+3+
×3+…+11+
×11
=(1+2+3+…+11)+(
+
×2+
×3+…+
×11)
=(1+2+3+…+11)+
×(1+2+3+…+11)
=[1+11)×5+6]+
×[(1+11)×5-6]
=66+
×66
=66+42
=108
點(diǎn)評(píng):分析題干中的數(shù)字,運(yùn)用運(yùn)算律,找簡(jiǎn)便方法進(jìn)行計(jì)算.