题目内容
神机妙算细又巧!(简算要写出简算过程)
2004×
= ;
3.68×〔1÷(2.1-2.09)〕= ;
0.2×1.25×50×7×8= ;
198÷
+202×
= .
2004×
2002 |
2003 |
3.68×〔1÷(2.1-2.09)〕=
0.2×1.25×50×7×8=
198÷
4 |
3 |
3 |
4 |
分析:(1)可将2004拆分为2003+1后根据乘法分配律计算;
(2)根据四则混合运算的运算顺序计算;
(3)可根据乘法交换律及结合律计算;
(4)可根据乘法分配律计算.
(2)根据四则混合运算的运算顺序计算;
(3)可根据乘法交换律及结合律计算;
(4)可根据乘法分配律计算.
解答:解:(1)2004×
=(2003+1)×
,
=2003×
+1×
,
=2002+
,
=2002
;
(2)3.68×[1÷(2.1-2.09)]
=3.68×[1÷0.01],
=3.68×100,
=368;
(3)0.2×1.25×50×7×8
=(0.2×50)×(1.25×8)×7,
=10×10×7,
=700;
(4)198÷
+202×
=198×
+202×
,
=(198+202)×
,
=400×
,
=300.
故答案为:2002
、368、700、300.
2002 |
2003 |
=(2003+1)×
2002 |
2003 |
=2003×
2002 |
2003 |
2002 |
2003 |
=2002+
2002 |
2003 |
=2002
2002 |
2003 |
(2)3.68×[1÷(2.1-2.09)]
=3.68×[1÷0.01],
=3.68×100,
=368;
(3)0.2×1.25×50×7×8
=(0.2×50)×(1.25×8)×7,
=10×10×7,
=700;
(4)198÷
4 |
3 |
3 |
4 |
=198×
3 |
4 |
3 |
4 |
=(198+202)×
3 |
4 |
=400×
3 |
4 |
=300.
故答案为:2002
2002 |
2003 |
点评:完成本题要注意分析式中数据的特点,然后运用合适的方法计算.
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