题目内容
看谁算得准(能简算要简算).
(54+
)÷9
41×99+41
÷[
×(0.4+
)].
(54+
9 |
10 |
41×99+41
9 |
20 |
3 |
2 |
4 |
5 |
分析:第(1)题,把除法改为乘法,然后用乘法分配律简算;
第(2)题,把41看作41×1,用乘法分配律的逆运算简算;
第(3)题,按运算顺序进行计算.
第(2)题,把41看作41×1,用乘法分配律的逆运算简算;
第(3)题,按运算顺序进行计算.
解答:解:(1)(54+
)÷9,
=(54+
)×
,
=54×
+
×
,
=6+
,
=6
;
(2)41×99+41,
=(99+1)×41,
=100×41,
=4100;
(3)
÷[
×(0.4+
)],
=
÷[
×(
+
)],
=
÷
,
=
×
,
=
.
9 |
10 |
=(54+
9 |
10 |
1 |
9 |
=54×
1 |
9 |
9 |
10 |
1 |
9 |
=6+
1 |
10 |
=6
1 |
10 |
(2)41×99+41,
=(99+1)×41,
=100×41,
=4100;
(3)
9 |
20 |
3 |
2 |
4 |
5 |
=
9 |
20 |
3 |
2 |
2 |
5 |
4 |
5 |
=
9 |
20 |
9 |
5 |
=
9 |
20 |
5 |
9 |
=
1 |
4 |
点评:此题考查了学生对运算顺序的掌握,以及运用运算定律简算的能力.在做此类题时,要注意审题,能简算的一定要简算.

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