题目内容
(2012?康县)
| 计算.(能简算的要简算) 61
|
24×(
| ||||||||||
360÷[56×(
|
(
| ||||||||||
| 80.7×8.7+8.07×13 |
|
分析:(1)根据数字特点,运用加法交换律与结合律以及减法的性质简算;
(2)(5)运用乘法分配律简算;
(3)中括号内运用乘法分配律简算,然后算括号外的除法;
(4)括号内运用乘法分配律简算,然后算括号外的除法;
(6)中括号内运用减法的性质简算,然后算括号外的乘法.
(2)(5)运用乘法分配律简算;
(3)中括号内运用乘法分配律简算,然后算括号外的除法;
(4)括号内运用乘法分配律简算,然后算括号外的除法;
(6)中括号内运用减法的性质简算,然后算括号外的乘法.
解答:解:(1)61
-15.37+38
-34.63,
=(61
+38
)-(15.37+34.63),
=100-50,
=50;
(2)24×(
+
-
),
=24×
+24×
-24×
,
=9+20-18,
=11;
(3)360÷[56×(
-
)],
=360÷[56×
-56×
],
=360÷[24-21],
=360÷3,
=120;
(4)(
×1.7+
×1.7)÷
,
=(
+
)×1.7×
,
=1×
×
,
=
;
(5)80.7×8.7+8.07×13,
=8.07×87+8.07×13,
=8.07×(87+13),
=8.07×100,
=807;
(6)
×[
-(
-
)],
=
×[
-
+
],
=
×[1-
],
=
×
,
=
.
| 3 |
| 4 |
| 1 |
| 4 |
=(61
| 3 |
| 4 |
| 1 |
| 4 |
=100-50,
=50;
(2)24×(
| 3 |
| 8 |
| 5 |
| 6 |
| 3 |
| 4 |
=24×
| 3 |
| 8 |
| 5 |
| 6 |
| 3 |
| 4 |
=9+20-18,
=11;
(3)360÷[56×(
| 3 |
| 7 |
| 3 |
| 8 |
=360÷[56×
| 3 |
| 7 |
| 3 |
| 8 |
=360÷[24-21],
=360÷3,
=120;
(4)(
| 6 |
| 13 |
| 7 |
| 13 |
| 7 |
| 10 |
=(
| 6 |
| 13 |
| 7 |
| 13 |
| 10 |
| 7 |
=1×
| 17 |
| 10 |
| 10 |
| 7 |
=
| 17 |
| 7 |
(5)80.7×8.7+8.07×13,
=8.07×87+8.07×13,
=8.07×(87+13),
=8.07×100,
=807;
(6)
| 8 |
| 9 |
| 3 |
| 5 |
| 9 |
| 16 |
| 2 |
| 5 |
=
| 8 |
| 9 |
| 3 |
| 5 |
| 9 |
| 16 |
| 2 |
| 5 |
=
| 8 |
| 9 |
| 9 |
| 16 |
=
| 8 |
| 9 |
| 7 |
| 16 |
=
| 7 |
| 18 |
点评:此题是考查四则混合运算,要仔细观察算式的特点,灵活运用一些定律进行简便计算.
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