题目内容
计算下列各题,能简便要用简便方法计算
×
+45×
; 4+
×
;
×
+
÷8; (
-
+
)×35.
1 |
2 |
1 |
3 |
5 |
9 |
4 |
5 |
5 |
6 |
7 |
8 |
2 |
3 |
2 |
3 |
19 |
35 |
1 |
5 |
1 |
7 |
考点:分数的四则混合运算
专题:运算顺序及法则
分析:(1)(2)先算乘法,再算加法;
(3)(4)利用乘法分配律简算.
(3)(4)利用乘法分配律简算.
解答:
解:(1)
×
+45×
=
+25
=25
;
(2)4+
×
=4+
=4
;
(3)
×
+
÷8
=
×
+
×
=(
+
)×
=1×
=
;
(4)(
-
+
)×35
=
×35-
×35+
×35
=19-7+5
=17.
1 |
2 |
1 |
3 |
5 |
9 |
=
1 |
6 |
=25
1 |
6 |
(2)4+
4 |
5 |
5 |
6 |
=4+
2 |
3 |
=4
2 |
3 |
(3)
7 |
8 |
2 |
3 |
2 |
3 |
=
7 |
8 |
2 |
3 |
2 |
3 |
1 |
8 |
=(
7 |
8 |
1 |
8 |
2 |
3 |
=1×
2 |
3 |
=
2 |
3 |
(4)(
19 |
35 |
1 |
5 |
1 |
7 |
=
19 |
35 |
1 |
5 |
1 |
7 |
=19-7+5
=17.
点评:混合运算的关键是抓住运算顺序,正确按运算顺序计算,适当利用运算定律简算.
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