5 / 6 × {- 1 / 8} × {2 / 5} × {- 4 / 9} .

5 / 6 × {- 1 / 8} × {2 / 5} × {- 4 / 9} .

5 / 6 × {- 1 / 8} × {2 / 5} × {- 4 / 9}
=5/6x9/8x12/5x4/9
=(5/6x12/5)x(9/8x4/9)
=2x1/2
=1
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One eighth divided by [one fifth multiplied by (two fifths + one tenth)] is a simple calculation

One eighth divided by [one fifth multiplied by (two fifths + one tenth)]
=1/8÷(1/5x2/5+1/5x1/10)
=1/8÷（4/50+1/50）
＝1/8÷1/10
＝5/4

A simple method is used to calculate the process

[5/9-(7/8-0.875)]÷4/9 =[5/9-(0.875-0.875)]÷4/9 =5/9÷4/9 =5/9×9/4 =5/4

(half minus one third multiplied by 50%) divided by 2.5 is a simple method

(half minus one-third times 50%) divided by 2.5%
=（1/2-1/3*1/2）*2/5
=1/2*2/5*（1-1/3）
=1/5*2/3
=2/15