Question

简便运算： 78*999+125*72 2.5*[789-(543+177)] 1.64*2.5-0.504÷1.8 5分之4*[8分之7-（2分之1*4分之1）]

Answer 1

78*999+125*72
=78×(1000-1)+125×8×9
=78000-78+9000
=87000-78
=86922;
2.5*[789-(543+177)]
=2.5×[789-720]
=2.5×69
=2.5×[70-1]
=175-2.5
=172.5;
1.64*2.5-0.504÷1.8
=4.1-0.28
=3.82;
5分之4*[8分之7-（2分之1*4分之1）]
=(4/5)×[7/8-1/8]
=(4/5)×(3/4)
=3/5;
如果本题有什么不明白可以追问，如果满意记得采纳
如果有其他问题请采纳本题后另发点击向我求助，答题不易，请谅解，谢谢。
祝学习进步

Answer 2

您好：

78*999+125*72
=78x1000-78x1+125x8x9
=7800-78+9000
=6900-78
=6822

2.5*[789-(543+177)]
=2.5x(789-720)
=2.5x69
=2.5x70-2.5x1
=175-2.5
=172.5

1.64*2.5-0.504÷1.8
=0.41x4x2.5-0.28
=0.41x10-0.28
=4.1-0.28
=3.82

5分之4*[8分之7-（2分之1*4分之1）]
=4/5x(7/8-1/8)
=4/5x3/4
=3/5

如果本题有什么不明白可以追问，如果满意记得采纳
如果有其他问题请采纳本题后另发点击向我求助，答题不易，请谅解，谢谢。
祝学习进步！

Answer 3

1、 原式等于：78X(1000-1)+125x8x9
=78000-78+1000x9
=77922+9000
=86922
2、原式等于：2.5x[789-720]
=2.5x69
=2.5x(24+45)
=2.5x4x6+2.5x9x5
=60+2.5x(10-1)x5
=60+(125-12.5)
=60+112.5
=172.5
3、原式等于：4x0.41x2.5-0.5
=0.4x10-0.5
=4-0.5
=3.5
4、原式等于：0.4x2.5÷1.8x2.5
=1÷4.5
=2/9
5、原式等于：4/5x[7/8-（1/2x1/4）]
=4/5x7/8-4/5x1/4x1/2
=7/10-1/5x1/2
=7/10-1/10
=6/10
=3/5。
希望能对你有所帮助！

Answer 4

29482212.5