题目内容
脱式计算,能简便的简便.
4.2-1.38+5.8-3.62 | 0.125×0.25×32 | ||||||||||
2÷
|
3
|
分析:(1)4.2-1.38+5.8-3.62,根据加、减法的运算性质进行简算;
(2)0.125×0.25×32,把32分解为:8×4,再运用乘法交换律和结合律进行简算;
(3)2÷
-
÷2,根据分数四则混合运算的顺序,按照它们的计算法则进行计算;
(4)3
×2.65-3
+3
×8.35,利用乘法分配律简算.
(2)0.125×0.25×32,把32分解为:8×4,再运用乘法交换律和结合律进行简算;
(3)2÷
2 |
3 |
2 |
3 |
(4)3
3 |
5 |
3 |
5 |
3 |
5 |
解答:解:(1)4.2-1.38+5.8-3.62,
=4.2+5.8-(1.38+3.62),
=10-5,
=5;
(2)0.125×0.25×32,
=(0.125×8)×(0.25×4),
=1×1,
=1;
(3)2÷
-
÷2,
=2×
-
×
,
=3-
,
=2
;
(4)3
×2.65-3
+3
×8.35,
=3.6×(2.65+8.35-1),
=3.6×10,
=36.
=4.2+5.8-(1.38+3.62),
=10-5,
=5;
(2)0.125×0.25×32,
=(0.125×8)×(0.25×4),
=1×1,
=1;
(3)2÷
2 |
3 |
2 |
3 |
=2×
3 |
2 |
2 |
3 |
1 |
2 |
=3-
1 |
3 |
=2
2 |
3 |
(4)3
3 |
5 |
3 |
5 |
3 |
5 |
=3.6×(2.65+8.35-1),
=3.6×10,
=36.
点评:此题考查的目的是掌握分数四则混合运算的顺序和它们的计算法则,并且能够灵活运用运算性质、运算定律进行简便计算.
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