题目内容
脱式计算
(1)
+
-
×6
(2)
÷
+
×
(3)(
+
-
)÷
×20;
(4)[4-(
-
)]×
(5)[2-(
+
)]÷
(6)(
×
-
)×21.
(1)
| 4 |
| 15 |
| 1 |
| 3 |
| 1 |
| 12 |
(2)
| 7 |
| 9 |
| 11 |
| 5 |
| 2 |
| 9 |
| 5 |
| 11 |
(3)(
| 5 |
| 12 |
| 1 |
| 6 |
| 7 |
| 12 |
| 1 |
| 7 |
(4)[4-(
| 3 |
| 4 |
| 3 |
| 8 |
| 4 |
| 29 |
(5)[2-(
| 1 |
| 4 |
| 3 |
| 8 |
| 1 |
| 4 |
(6)(
| 7 |
| 15 |
| 5 |
| 14 |
| 1 |
| 7 |
分析:(1)(3)(4)(5)(6)依据四则运算顺序:先算第二级运算,再算第一级运算,如果只含有同一级运算,按照从左到右顺序计算,有括号先算括号里面的顺序解答即可解答,
(2)运用乘法分配律解答.
(2)运用乘法分配律解答.
解答:解:(1)
+
-
×6,
=
+
-
,
=
-
,
=
;
(2)
÷
+
×
,
=(
+
)×
,
=1×
,
=
;
(3)(
+
-
)÷
×20,
=(
-
)÷
×20,
=0÷
×20,
=0;
(4)[4-(
-
)]×
,
=[4-
]×
,
=
×
,
=
;
(5)[2-(
+
)]÷
,
=[2-
]÷
,
=
÷
,
=
;
(6)(
×
-
)×21,
=(
-
)×21,
=
×21,
=
.
| 4 |
| 15 |
| 1 |
| 3 |
| 1 |
| 12 |
=
| 4 |
| 15 |
| 1 |
| 3 |
| 1 |
| 2 |
=
| 9 |
| 15 |
| 1 |
| 2 |
=
| 1 |
| 10 |
(2)
| 7 |
| 9 |
| 11 |
| 5 |
| 2 |
| 9 |
| 5 |
| 11 |
=(
| 7 |
| 9 |
| 2 |
| 9 |
| 5 |
| 11 |
=1×
| 5 |
| 11 |
=
| 5 |
| 11 |
(3)(
| 5 |
| 12 |
| 1 |
| 6 |
| 7 |
| 12 |
| 1 |
| 7 |
=(
| 7 |
| 12 |
| 7 |
| 12 |
| 1 |
| 7 |
=0÷
| 1 |
| 7 |
=0;
(4)[4-(
| 3 |
| 4 |
| 3 |
| 8 |
| 4 |
| 29 |
=[4-
| 3 |
| 8 |
| 4 |
| 29 |
=
| 29 |
| 8 |
| 4 |
| 29 |
=
| 1 |
| 2 |
(5)[2-(
| 1 |
| 4 |
| 3 |
| 8 |
| 1 |
| 4 |
=[2-
| 5 |
| 8 |
| 1 |
| 4 |
=
| 11 |
| 8 |
| 1 |
| 4 |
=
| 11 |
| 2 |
(6)(
| 7 |
| 15 |
| 5 |
| 14 |
| 1 |
| 7 |
=(
| 1 |
| 6 |
| 1 |
| 7 |
=
| 1 |
| 42 |
=
| 1 |
| 2 |
点评:(1)依据四则运算顺序正确进行计算,(2)运用乘法分配律正确解决问题,是本题考查知识点.
练习册系列答案
相关题目