题目内容
能简便计算的写出简算过程![]() | ![]() | ![]() | ![]() |
![]() | ![]() | ![]() | (0.75![]() ![]() |
解:(1)
×
×
,
=
;
(2)
÷
×
,
=
×
×
,
=
;
(3)5-
÷
-
,
=5-
×
-
,
=5-
-
,
=5-(
+
),
=5-2,
=3;
(4)
×
+
,
=
×
+
×
,
=
×
×2,
=
;
(5)
×[0.5÷(
×
)],
=
×[
÷
],
=
×[
×
],
=
×
,
=
;
(6)
×
×
,
=
;
(7)
÷
,
=
×
×
,
=
;
(8)(0.75-
)×(
+
),
=(
-
)×
,
=
×
,
=
.
分析:(1)约分计算;
(2)把除法改为乘法,通过约分即可;
(3)先算除法,然后运用减法的性质简算;
(4)把除法改为乘法,加号两边的算式相同,用一个乘2即可;
(5)把0.5改为
,先算小括号内的,再算中括号内的,最后算括号外的;
(6)与第(1)题相同;
(7)把除法改为乘法,约分计算;
(8)把小数化为分数,两个括号同时计算.
点评:此题主要考查分数、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的能力.



=

(2)



=



=

(3)5-



=5-



=5-


=5-(


=5-2,
=3;
(4)




=




=


=

(5)



=



=



=


=

(6)



=

(7)


=



=

(8)(0.75-



=(



=


=

分析:(1)约分计算;
(2)把除法改为乘法,通过约分即可;
(3)先算除法,然后运用减法的性质简算;
(4)把除法改为乘法,加号两边的算式相同,用一个乘2即可;
(5)把0.5改为

(6)与第(1)题相同;
(7)把除法改为乘法,约分计算;
(8)把小数化为分数,两个括号同时计算.
点评:此题主要考查分数、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的能力.

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