题目内容
计算.
①[14.8+(3
-1.5)×1
]÷2
②
÷2
-1.4×
+7+
×20%
①[14.8+(3
| 2 |
| 7 |
| 3 |
| 25 |
| 2 |
| 3 |
②
| 10 |
| 13 |
| 19 |
| 22 |
| 11 |
| 13 |
| 22 |
| 63 |
分析:①先算小括号里面的减法,再算中括号里面的乘法,然后算中括号里面的加法,最后算括号外的除法;
②先把除法变成乘法,运用乘法交换律和乘法分配律简算,再运用加法交换律简算.
②先把除法变成乘法,运用乘法交换律和乘法分配律简算,再运用加法交换律简算.
解答:解:①[14.8+(3
-1.5)×1
]÷2
,
=[14.8+
×
]÷2
,
=[14.8+2]÷2
,
=16.8×
,
=6.3;
②
÷2
-1.4×
+7+
×20%,
=
×
-1.4×
+7+
×20%,
=
×
+
×20%-1.4×
+7,
=
×(
+0.2)-1.4×
+7,
=
×
-1.4×
+7,
=
-
+7,
=7-(
-
),
=7-
,
=6
.
| 2 |
| 7 |
| 3 |
| 25 |
| 2 |
| 3 |
=[14.8+
| 25 |
| 14 |
| 28 |
| 25 |
| 2 |
| 3 |
=[14.8+2]÷2
| 2 |
| 3 |
=16.8×
| 3 |
| 8 |
=6.3;
②
| 10 |
| 13 |
| 19 |
| 22 |
| 11 |
| 13 |
| 22 |
| 63 |
=
| 10 |
| 13 |
| 22 |
| 63 |
| 11 |
| 13 |
| 22 |
| 63 |
=
| 10 |
| 13 |
| 22 |
| 63 |
| 22 |
| 63 |
| 11 |
| 13 |
=
| 22 |
| 63 |
| 10 |
| 13 |
| 11 |
| 13 |
=
| 22 |
| 63 |
| 63 |
| 65 |
| 11 |
| 13 |
=
| 22 |
| 65 |
| 77 |
| 65 |
=7-(
| 77 |
| 65 |
| 22 |
| 65 |
=7-
| 11 |
| 13 |
=6
| 2 |
| 13 |
点评:本题考查了四则混合运算,注意运算顺序和运算法则,灵活运用所学的运算定律进行简便计算.
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