题目内容
(2007?楚州区)脱式计算(能简算的要简算):
÷[
-(
+
)]
÷
+
×
0.125×32×25.
| 8 |
| 25 |
| 11 |
| 10 |
| 2 |
| 5 |
| 1 |
| 10 |
| 5 |
| 8 |
| 2 |
| 3 |
| 3 |
| 8 |
| 3 |
| 2 |
0.125×32×25.
分析:(1)此题按运算顺序计算,先算小括号内的,再算中括号内的,最后算括号外的;
(2)把除法改为乘法,然后用乘法分配律的逆运算简算;
(3)把32看作8×4,然后用乘法交换律与结合律简算.
(2)把除法改为乘法,然后用乘法分配律的逆运算简算;
(3)把32看作8×4,然后用乘法交换律与结合律简算.
解答:解:(1)
÷[
-(
+
)],
=
÷[
-
-
],
=
÷[1-
],
=
÷
,
=
×
,
=
;
(2)
÷
+
×
,
=
×
+
×
,
=(
+
)×
,
=1×
,
=
;
(3)0.125×32×25,
=0.125×8×4×25,
=(0.125×8)×(4×25),
=1×100,
=100.
| 8 |
| 25 |
| 11 |
| 10 |
| 2 |
| 5 |
| 1 |
| 10 |
=
| 8 |
| 25 |
| 11 |
| 10 |
| 1 |
| 10 |
| 2 |
| 5 |
=
| 8 |
| 25 |
| 2 |
| 5 |
=
| 8 |
| 25 |
| 3 |
| 5 |
=
| 8 |
| 25 |
| 5 |
| 3 |
=
| 8 |
| 15 |
(2)
| 5 |
| 8 |
| 2 |
| 3 |
| 3 |
| 8 |
| 3 |
| 2 |
=
| 5 |
| 8 |
| 3 |
| 2 |
| 3 |
| 8 |
| 3 |
| 2 |
=(
| 5 |
| 8 |
| 3 |
| 8 |
| 3 |
| 2 |
=1×
| 3 |
| 2 |
=
| 3 |
| 2 |
(3)0.125×32×25,
=0.125×8×4×25,
=(0.125×8)×(4×25),
=1×100,
=100.
点评:本题主要考查对四则混合运算法则的正确运用,同时也考查了学生对运算定律的灵活运用能力.
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