题目内容
计算题
(1)
÷
+
÷
(2)
+2
+
+3
(3)(
×
+
)÷
(4)
×[
-(
-
)].
(1)
| 3 |
| 76 |
| 1 |
| 10 |
| 3 |
| 76 |
| 1 |
| 9 |
(2)
| 3 |
| 4 |
| 9 |
| 17 |
| 1 |
| 4 |
| 8 |
| 17 |
(3)(
| 8 |
| 11 |
| 11 |
| 40 |
| 2 |
| 5 |
| 2 |
| 3 |
(4)
| 8 |
| 9 |
| 3 |
| 4 |
| 7 |
| 16 |
| 1 |
| 4 |
分析:算式(1)可根据分数除法的计算法则将式中的除法算式变为乘法算式后,根据乘法分配律计算;
算式(2)可根据加法交换律及结合律计算;
算式(3)根据四则混合运算的运算顺序计算即可;
算式(4)可根据一个数减两个数的差,等于用这个数减去两个数中的被减数,加上减数的减法性质及加法交换律进行计算.
算式(2)可根据加法交换律及结合律计算;
算式(3)根据四则混合运算的运算顺序计算即可;
算式(4)可根据一个数减两个数的差,等于用这个数减去两个数中的被减数,加上减数的减法性质及加法交换律进行计算.
解答:解:(1)
÷
+
÷
=
×10+
×9,
=
×(10+9),
=
×19,
=
;
(2)
+2
+
+3
=(
+
)+(2
+3
),
=1+6,
=7;
(3)(
×
+
)÷
=(
+
)×
,
=
×
,
=
;
(4)
×[
-(
-
)]
=
×[
+
-
],
=
×[1-
],
=
×
,
=
.
| 3 |
| 76 |
| 1 |
| 10 |
| 3 |
| 76 |
| 1 |
| 9 |
=
| 3 |
| 76 |
| 3 |
| 76 |
=
| 3 |
| 76 |
=
| 3 |
| 76 |
=
| 3 |
| 4 |
(2)
| 3 |
| 4 |
| 9 |
| 17 |
| 1 |
| 4 |
| 8 |
| 17 |
=(
| 3 |
| 4 |
| 1 |
| 4 |
| 9 |
| 17 |
| 8 |
| 17 |
=1+6,
=7;
(3)(
| 8 |
| 11 |
| 11 |
| 40 |
| 2 |
| 5 |
| 2 |
| 3 |
=(
| 1 |
| 5 |
| 2 |
| 5 |
| 3 |
| 2 |
=
| 3 |
| 5 |
| 3 |
| 2 |
=
| 9 |
| 10 |
(4)
| 8 |
| 9 |
| 3 |
| 4 |
| 7 |
| 16 |
| 1 |
| 4 |
=
| 8 |
| 9 |
| 3 |
| 4 |
| 1 |
| 4 |
| 7 |
| 16 |
=
| 8 |
| 9 |
| 7 |
| 16 |
=
| 8 |
| 9 |
| 9 |
| 16 |
=
| 1 |
| 2 |
点评:完成此类题目要认真分析式中数据的特点及内在联系,然后选择合适的方法进行计算.
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