题目内容
下面各题,怎样简便怎样算.
85×54÷18+745
13.5÷[1.5×(1.07+1.93)]
÷[
-(
+
)]
×
+
÷13.
85×54÷18+745
13.5÷[1.5×(1.07+1.93)]
| 8 |
| 49 |
| 9 |
| 8 |
| 1 |
| 8 |
| 3 |
| 7 |
| 7 |
| 8 |
| 12 |
| 13 |
| 7 |
| 8 |
考点:整数四则混合运算,运算定律与简便运算,整数、分数、小数、百分数四则混合运算
专题:运算顺序及法则,运算定律及简算
分析:(1)先算乘法,再算除法,最后算加法;
(2)先算加法,再算乘法,最后算除法;
(3)括号内利用减法的性质简算,再算除法;
(4)利用乘法分配律简算.
(2)先算加法,再算乘法,最后算除法;
(3)括号内利用减法的性质简算,再算除法;
(4)利用乘法分配律简算.
解答:
解:(1)85×54÷18+745
=4590÷18+745
=255+745
=1000;
(2)13.5÷[1.5×(1.07+1.93)]
=13.5÷[1.5×3]
=13.5÷4.5
=3;
(3)
÷[
-(
+
)]
=
÷[
-
-
]
=
÷[1-
]
=
×
=
;
(4)
×
+
÷13
=
×
+
×
=
×(
+
)
=
×1
=
.
=4590÷18+745
=255+745
=1000;
(2)13.5÷[1.5×(1.07+1.93)]
=13.5÷[1.5×3]
=13.5÷4.5
=3;
(3)
| 8 |
| 49 |
| 9 |
| 8 |
| 1 |
| 8 |
| 3 |
| 7 |
=
| 8 |
| 49 |
| 9 |
| 8 |
| 1 |
| 8 |
| 3 |
| 7 |
=
| 8 |
| 49 |
| 3 |
| 7 |
=
| 8 |
| 49 |
| 7 |
| 4 |
=
| 2 |
| 7 |
(4)
| 7 |
| 8 |
| 12 |
| 13 |
| 7 |
| 8 |
=
| 7 |
| 8 |
| 12 |
| 13 |
| 7 |
| 8 |
| 1 |
| 13 |
=
| 7 |
| 8 |
| 12 |
| 13 |
| 1 |
| 13 |
=
| 7 |
| 8 |
=
| 7 |
| 8 |
点评:混合运算的关键是搞清运算顺序,正确按运算顺序计算,适当利用运算定律简算.
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