题目内容
【题目】(18分)
计算(能简算的要简算).
(3618÷18﹣145)×20 6÷﹣
÷6
÷[
×(
+
)]
125×25×32 3.5×9.8+3.5×0.2 ×
﹣
÷13.
【答案】(3618÷18﹣145)×20,
=(201﹣145)×20,
=56×20,
=1120;
6÷﹣
÷6,
=6×﹣
×
,
=10﹣,
=9;
÷[
×(
+
)],
=÷[
×
],
=÷
,
=×
,
=;
125×25×32,
=125×25×(4×8),
=(125×8)×(25×4),
=1000×100,
=100000;
3.5×9.8+3.5×0.2,
=3.5×(9.8+0.2),
=3.5×10,
=35;
×
﹣
÷13,
=×
﹣
×
,
=(﹣
)×
,
=×
,
=.
【解析】
试题分析:(3618÷18﹣145)×20,先计算小括号里的除法,再计算小括号里的减法,最后计算乘法;
6÷﹣
÷6,先计算除法,最后计算减法;
÷[
×(
+
)],先计算小括号里的加法,再计算中括号的乘法,最后计算除法;
125×25×32,把32看作4×8,再根据乘法交换律和结合律进行简算;
3.5×9.8+3.5×0.2,根据乘法分配律进行简算;
×
﹣
÷13,根据乘法分配律进行简算.
解:(3618÷18﹣145)×20,
=(201﹣145)×20,
=56×20,
=1120;
6÷﹣
÷6,
=6×﹣
×
,
=10﹣,
=9;
÷[
×(
+
)],
=÷[
×
],
=÷
,
=×
,
=;
125×25×32,
=125×25×(4×8),
=(125×8)×(25×4),
=1000×100,
=100000;
3.5×9.8+3.5×0.2,
=3.5×(9.8+0.2),
=3.5×10,
=35;
×
﹣
÷13,
=×
﹣
×
,
=(﹣
)×
,
=×
,
=.
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