题目内容
能简算的要简算
7×
(
+
)×0.8
×
+
×
×8×
+
×
44-72×
.
7×
| 9 |
| 16 |
| 3 |
| 4 |
| 5 |
| 8 |
| 5 |
| 9 |
| 3 |
| 4 |
| 5 |
| 9 |
| 1 |
| 4 |
| 5 |
| 4 |
| 1 |
| 6 |
| 1 |
| 5 |
| 2 |
| 9 |
| 3 |
| 10 |
| 5 |
| 12 |
考点:分数的四则混合运算
专题:运算顺序及法则
分析:(1)直接利用乘法计算;
(2)(3)利用乘法分配律简算;
(4)按照从左到右的顺序计算;
(5)先算乘法,再算加法;
(6)先算乘法,再算减法.
(2)(3)利用乘法分配律简算;
(4)按照从左到右的顺序计算;
(5)先算乘法,再算加法;
(6)先算乘法,再算减法.
解答:
解:(1)7×
=
;
(2)(
+
)×0.8
=(
+
)×
=
×
+
×
=
+
=
;
(3)
×
+
×
=
×(
+
)
=
×1
=
;
(4)
×8×
=10×
=
;
(5)
+
×
=
+
=
;
(6)44-72×
=44-30
=14.
| 9 |
| 16 |
| 63 |
| 16 |
(2)(
| 3 |
| 4 |
| 5 |
| 8 |
=(
| 3 |
| 4 |
| 5 |
| 8 |
| 4 |
| 5 |
=
| 3 |
| 4 |
| 4 |
| 5 |
| 5 |
| 8 |
| 4 |
| 5 |
=
| 3 |
| 5 |
| 1 |
| 2 |
=
| 11 |
| 10 |
(3)
| 5 |
| 9 |
| 3 |
| 4 |
| 5 |
| 9 |
| 1 |
| 4 |
=
| 5 |
| 9 |
| 3 |
| 4 |
| 1 |
| 4 |
=
| 5 |
| 9 |
=
| 5 |
| 9 |
(4)
| 5 |
| 4 |
| 1 |
| 6 |
=10×
| 1 |
| 6 |
=
| 5 |
| 3 |
(5)
| 1 |
| 5 |
| 2 |
| 9 |
| 3 |
| 10 |
=
| 1 |
| 5 |
| 3 |
| 45 |
=
| 12 |
| 45 |
(6)44-72×
| 5 |
| 12 |
=44-30
=14.
点评:分数四则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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