题目内容
(2009?湛河区)脱式计算,能简算的要简算.
(1)0.6+6×32×0.25
(2)(
+
)÷
-
(3)36×(
+
-
)
(4)
×[
-(
+
)].
(1)0.6+6×32×0.25
(2)(
| 4 |
| 5 |
| 1 |
| 4 |
| 7 |
| 3 |
| 1 |
| 4 |
(3)36×(
| 7 |
| 9 |
| 1 |
| 4 |
| 5 |
| 6 |
(4)
| 8 |
| 9 |
| 7 |
| 8 |
| 7 |
| 16 |
| 1 |
| 8 |
分析:(1)把32分解成8×4,然后用乘法结合律简算;
(2)先算小括号里面的加法,再算括号外的除法,最后算减法;
(3)运用乘法分配律简算;
(4)先去掉小括号,再把中括号里面的运算用加法交换律简算,最后算括号外的乘法.
(2)先算小括号里面的加法,再算括号外的除法,最后算减法;
(3)运用乘法分配律简算;
(4)先去掉小括号,再把中括号里面的运算用加法交换律简算,最后算括号外的乘法.
解答:解:(1)0.6+6×32×0.25,
=0.6+(6×8)×(4×0.25),
=0.6+48×1,
=0.6+48,
=48.6;
(2)(
+
)÷
-
,
=
×
-
,
=
-
,
=
;
(3)36×(
+
-
),
=36×
+36×
-36×
,
=28+9-30,
=7;
(4)
×[
-(
+
)],
=
×[
-
+
],
=
×[
+
-
],
=
×[1-
],
=
×
,
=
.
=0.6+(6×8)×(4×0.25),
=0.6+48×1,
=0.6+48,
=48.6;
(2)(
| 4 |
| 5 |
| 1 |
| 4 |
| 7 |
| 3 |
| 1 |
| 4 |
=
| 21 |
| 20 |
| 3 |
| 7 |
| 1 |
| 4 |
=
| 9 |
| 20 |
| 1 |
| 4 |
=
| 1 |
| 5 |
(3)36×(
| 7 |
| 9 |
| 1 |
| 4 |
| 5 |
| 6 |
=36×
| 7 |
| 9 |
| 1 |
| 4 |
| 5 |
| 6 |
=28+9-30,
=7;
(4)
| 8 |
| 9 |
| 7 |
| 8 |
| 7 |
| 16 |
| 1 |
| 8 |
=
| 8 |
| 9 |
| 7 |
| 8 |
| 7 |
| 16 |
| 1 |
| 8 |
=
| 8 |
| 9 |
| 7 |
| 8 |
| 1 |
| 8 |
| 7 |
| 16 |
=
| 8 |
| 9 |
| 7 |
| 16 |
=
| 8 |
| 9 |
| 9 |
| 16 |
=
| 1 |
| 2 |
点评:运算定律是常用的简便运算的方法,要熟练掌握,灵活运用.
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