A few calculation problems, 1.（-5/6）÷（-19/6）÷[1/24×（-5/4）]-0.25÷1/4 2.-1-4/13×[-4-9]×[（-8）+0÷（-1）] 3.-9×4/9÷（-0.8）+4+（-4）-（-9）

A few calculation problems, 1.（-5/6）÷（-19/6）÷[1/24×（-5/4）]-0.25÷1/4 2.-1-4/13×[-4-9]×[（-8）+0÷（-1）] 3.-9×4/9÷（-0.8）+4+（-4）-（-9）

=-5/6*-6/19*-96/5-0.25
=5/19*-96/5-0.25÷1/4
=-96/19-1
=-77-19
the second
=-1-4/13*-13*-8
=-1+4*-8
=-1-32
=-33
Third
=-4÷-0.8+4-4+9
=5+4-4+9
=14

（1）-4.2+5.7-8.4+10
(2) - 1 / 4 + 5 / 6 + 2 / 3 - 1 / 2
（3）12-（-18）+（-7）-15
（4）4.7-（-8.9）-7.5+（-6）
(5) (- four and seven eighths) - (- five and one half) + (- four and one fourth) - (+ three and one eighth)
(6) (- two thirds) + | 0 - five and one sixth + | - four and five sixth + (- nine and one third)

(1) - 4.2 + 5.7-8.4 + 10 = 1.5-8.4 + 10 = - 6.9 + 10 = 3.1 (2) - quarter + five sixths + two thirds - half = - 1 / 4 + 5 / 6 + 4 / 6-3 / 6 = - 1 / 4 + 1 = 5 / 4 (3) 12 - (- 18) + - 7) - 15 = 12 + 18-7 = 30-7 = 23 (4) 4.7 - (- 8.9) - 7.5 + (- 6) = 4.7 + 8.9-7.5-6 = 0.1