计算,能简算的要写出简算过程.
32×2.5×12.5??????????????????
0.65×24+77×65%-65%
40÷[14-(45-39)]
2.25×4.8+77.5×0.48.
计算,能简算的要写出简算过程.32×2.5×12.5??????????????????0.65×24+77×65%-65%40÷[14-(45-39)]2.25×4
答案:2 悬赏:30 手机版
解决时间 2021-01-31 03:01
- 提问者网友:缘字诀
- 2021-01-30 20:38
最佳答案
- 五星知识达人网友:野慌
- 2020-10-04 08:33
解:(1)32×2.5×12.5,
=4×8×2.5×12.5,
=(4×2.5)×(12.5×8),
=10×100,
=1000;
????????
(2)0.65×24+77×65%-65%,
=0.65×24+77×0.65-0.65,
=0.65×(24+77-1),
=0.65×100,
=65;
(3)40÷[14-(45-39)],
=40÷[14-6],
=40÷8,
=5;
(4)2.25×4.8+77.5×0.48,
=22.5×0.48+77.5×0.48,
=(22.5+77.5)×0.48,
=100×0.48,
=48.解析分析:(1)把32看作4×8,运用乘法交换律与结合律简算;
(2)把百分数化为小数,运用乘法分配律简算;
(3)先算小括号内的,再算中括号内的,最后算括号外的;
(4)根据数字特点,原式变为22.5×0.48+77.5×0.48,运用乘法分配律简算.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律简便计算.
=4×8×2.5×12.5,
=(4×2.5)×(12.5×8),
=10×100,
=1000;
????????
(2)0.65×24+77×65%-65%,
=0.65×24+77×0.65-0.65,
=0.65×(24+77-1),
=0.65×100,
=65;
(3)40÷[14-(45-39)],
=40÷[14-6],
=40÷8,
=5;
(4)2.25×4.8+77.5×0.48,
=22.5×0.48+77.5×0.48,
=(22.5+77.5)×0.48,
=100×0.48,
=48.解析分析:(1)把32看作4×8,运用乘法交换律与结合律简算;
(2)把百分数化为小数,运用乘法分配律简算;
(3)先算小括号内的,再算中括号内的,最后算括号外的;
(4)根据数字特点,原式变为22.5×0.48+77.5×0.48,运用乘法分配律简算.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律简便计算.
全部回答
- 1楼网友:旧脸谱
- 2020-06-04 10:35
这下我知道了
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