How to write these three mathematical problems? Multiplication and division of rational numbers in the first day of junior high school (- 3 / 7) × (7 / 3) —80×(—4120)×12.5×0.01 (1 / 2 + 5 / 6-7 / 12) × (- 36)  

How to write these three mathematical problems? Multiplication and division of rational numbers in the first day of junior high school (- 3 / 7) × (7 / 3) —80×(—4120)×12.5×0.01 (1 / 2 + 5 / 6-7 / 12) × (- 36)  

-1
—80×(—4120)×12.5×0.01=(80*12.5)*0.01*4120
=1000*0.01*4120=41200
(1 / 2 + 5 / 6-7 / 12) × (- 36) = - 18-30 + 21 = - 27