题目内容
脱式计算: 205×36-2940÷28 | ![]() ![]() ![]() | 0.75×![]() ![]() |
[11÷(![]() ![]() ![]() | 8.7-3.4×3.5÷1.7 | (![]() ![]() ![]() ![]() |
解:(1)205×36-2940÷28,
=7380-105,
=7275;
(2)
÷
×
,
=
×
×
,
=
;
(3)0.75×
+0.25÷
,
=0.75×
+0.25×
,
=(0.75+0.25)×
,
=1×
,
=
;
(4)[11÷(
+
)]×
,
=[11÷
]×
,
=11×
×
,
=
;
(5)8.7-3.4×3.5÷1.7,
=8.7-3.4÷1.7×3.5,
=8.7-2×3.5,
=8.7-7,
=1.7;
(6)(
+
)×(
-
),
=
×
,
=
.
分析:(1)先算乘除,再算减法;
(2)把除法改为乘法,约分计算;
(3)把除法改为乘法,运用乘法分配律简算;
(4)先算小括号内的,再算中括号内的,最后算括号外的;
(5,在计算3.4×3.5÷1.7,可调整一下运算顺序,即3.4÷1.7×3.5;
(6)两个括号同时计算,最后算乘法.
点评:此题主要考查分数、整数、小数的四则混合运算的运算顺序和应用运算定律进行简便计算.
=7380-105,
=7275;
(2)



=



=

(3)0.75×


=0.75×


=(0.75+0.25)×

=1×

=

(4)[11÷(



=[11÷


=11×


=

(5)8.7-3.4×3.5÷1.7,
=8.7-3.4÷1.7×3.5,
=8.7-2×3.5,
=8.7-7,
=1.7;
(6)(




=


=

分析:(1)先算乘除,再算减法;
(2)把除法改为乘法,约分计算;
(3)把除法改为乘法,运用乘法分配律简算;
(4)先算小括号内的,再算中括号内的,最后算括号外的;
(5,在计算3.4×3.5÷1.7,可调整一下运算顺序,即3.4÷1.7×3.5;
(6)两个括号同时计算,最后算乘法.
点评:此题主要考查分数、整数、小数的四则混合运算的运算顺序和应用运算定律进行简便计算.

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