题目内容
下面各题,能简算的要用简便方法计算. 2.9+0.46+7.1+0.54 |
(31.6-11.7)÷2.5÷0.4 |
0.4×37×25 | 4.97÷1.25+3.03×8. |
分析:①根据加法交换律和结合律;
②除以2.5再除以0.4,根据除法的简便运算,看作除以2.5×0.4=1;
③根据乘法交换律和结合律;
④1.25=
,除以
,等于乘
,然后根据乘法分配律,即可得解.
②除以2.5再除以0.4,根据除法的简便运算,看作除以2.5×0.4=1;
③根据乘法交换律和结合律;
④1.25=
10 |
8 |
10 |
8 |
8 |
10 |
解答:解:①2.9+0.46+7.1+0.54
=(2.9+7.1)+(0.46+0.54)
=10+1
=11;
②(31.6-11.7)÷2.5÷0.4
=19.9÷(2.5×0.4)
=19.9÷1
=19.9;
③0.4×37×25
=37×(0.4×25)
=37×10
=370;
④4.97÷1.25+3.03×8
=4.97÷
+3.03×8
=0.497×8+3.03×8
=(0.497+3.03)×8
=3.527×8
=28.216.
=(2.9+7.1)+(0.46+0.54)
=10+1
=11;
②(31.6-11.7)÷2.5÷0.4
=19.9÷(2.5×0.4)
=19.9÷1
=19.9;
③0.4×37×25
=37×(0.4×25)
=37×10
=370;
④4.97÷1.25+3.03×8
=4.97÷
10 |
8 |
=0.497×8+3.03×8
=(0.497+3.03)×8
=3.527×8
=28.216.
点评:考查了运算定律与简便运算,四则混合运算.注意运算顺序和运算法则,灵活运用所学的运算定律简便计算.
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